Various evolutionary ideas had already been proposed to explain new findings in biology. There was growing support for such ideas among dissident anatomists and the general public, but during the first half of the 19th century the English scientific establishment was closely tied to the Church of England, while science was part of natural theology. Ideas about the transmutation of species were controversial as they conflicted with the beliefs that species were unchanging parts of a designed hierarchy and that humans were unique, unrelated to other animals. The political and theological implications were intensely debated, but transmutation was not accepted by the scientific mainstream.


The book was written for non-specialist readers and attracted widespread interest upon its publication. As Darwin was an eminent scientist, his findings were taken seriously and the evidence he presented generated scientific, philosophical, and religious discussion. The debate over the book contributed to the campaign by T. H. Huxley and his fellow members of the X Club to secularise science by promoting scientific naturalism. Within two decades there was widespread scientific agreement that evolution, with a branching pattern of common descent, had occurred, but scientists were slow to give natural selection the significance that Darwin thought appropriate. During "the eclipse of Darwinism" from the 1880s to the 1930s, various other mechanisms of evolution were given more credit. With the development of the modern evolutionary synthesis in the 1930s and 1940s, Darwin's concept of evolutionary adaptation through natural selection became central to modern evolutionary theory, and it has now become the unifying concept of the life sciences.


In later editions of the book, Darwin traced evolutionary ideas as far back as Aristotle; the text he cites is a summary by Aristotle of the ideas of the earlier Greek philosopher Empedocles. Early Christian Church Fathers and Medieval European scholars interpreted the Genesis creation narrative allegorically rather than as a literal historical account; organisms were described by their mythological and heraldic significance as well as by their physical form. Nature was widely believed to be unstable and capricious, with monstrous births from union between species, and spontaneous generation of life.


The Protestant Reformation inspired a literal interpretation of the Bible, with concepts of creation that conflicted with the findings of an emerging science seeking explanations congruent with the mechanical philosophy of René Descartes and the empiricism of the Baconian method. After the turmoil of the English Civil War, the Royal Society wanted to show that science did not threaten religious and political stability. John Ray developed an influential natural theology of rational order; in his taxonomy, species were static and fixed, their adaptation and complexity designed by God, and varieties showed minor differences caused by local conditions. In God's benevolent design, carnivores caused mercifully swift death, but the suffering caused by parasitism was a puzzling problem. The biological classification introduced by Carl Linnaeus in 1735 also viewed species as fixed according to the divine plan. In 1766, Georges Buffon suggested that some similar species, such as horses and asses, or lions, tigers, and leopards, might be varieties descended from a common ancestor. The Ussher chronology of the 1650s had calculated creation at 4004 BC, but by the 1780s geologists assumed a much older world. Wernerians thought strata were deposits from shrinking seas, but James Hutton proposed a self-maintaining infinite cycle, anticipating uniformitarianism.


Charles Darwin's grandfather Erasmus Darwin outlined a hypothesis of transmutation of species in the 1790s, and Jean-Baptiste Lamarck published a more developed theory in 1809. Both envisaged that spontaneous generation produced simple forms of life that progressively developed greater complexity, adapting to the environment by inheriting changes in adults caused by use or disuse. This process was later called Lamarckism. Lamarck thought there was an inherent progressive tendency driving organisms continuously towards greater complexity, in parallel but separate lineages with no extinction. Geoffroy contended that embryonic development recapitulated transformations of organisms in past eras when the environment acted on embryos, and that animal structures were determined by a constant plan as demonstrated by homologies. Georges Cuvier strongly disputed such ideas, holding that unrelated, fixed species showed similarities that reflected a design for functional needs. His palæontological work in the 1790s had established the reality of extinction, which he explained by local catastrophes, followed by repopulation of the affected areas by other species.


In Britain, William Paley's Natural Theology saw adaptation as evidence of beneficial "design" by the Creator acting through natural laws. All naturalists in the two English universities (Oxford and Cambridge) were Church of England clergymen, and science became a search for these laws. Geologists adapted catastrophism to show repeated worldwide annihilation and creation of new fixed species adapted to a changed environment, initially identifying the most recent catastrophe as the biblical flood. Some anatomists such as Robert Grant were influenced by Lamarck and Geoffroy, but most naturalists regarded their ideas of transmutation as a threat to divinely appointed social order.


Darwin went to Edinburgh University in 1825 to study medicine. In his second year he neglected his medical studies for natural history and spent four months assisting Robert Grant's research into marine invertebrates. Grant revealed his enthusiasm for the transmutation of species, but Darwin rejected it. Starting in 1827, at Cambridge University, Darwin learnt science as natural theology from botanist John Stevens Henslow, and read Paley, John Herschel and Alexander von Humboldt. Filled with zeal for science, he studied catastrophist geology with Adam Sedgwick.


In December 1831, he joined the Beagle expedition as a gentleman naturalist and geologist. He read Charles Lyell's Principles of Geology and from the first stop ashore, at St. Jago, found Lyell's uniformitarianism a key to the geological history of landscapes. Darwin discovered fossils resembling huge armadillos, and noted the geographical distribution of modern species in hope of finding their "centre of creation". The three Fuegian missionaries the expedition returned to Tierra del Fuego were friendly and civilised, yet to Darwin their relatives on the island seemed "miserable, degraded savages", and he no longer saw an unbridgeable gap between humans and animals. As the Beagle neared England in 1836, he noted that species might not be fixed.


Richard Owen showed that fossils of extinct species Darwin found in South America were allied to living species on the same continent. In March 1837, ornithologist John Gould announced that Darwin's rhea was a separate species from the previously described rhea (though their territories overlapped), that mockingbirds collected on the Galápagos Islands represented three separate species each unique to a particular island, and that several distinct birds from those islands were all classified as finches. Darwin began speculating, in a series of notebooks, on the possibility that "one species does change into another" to explain these findings, and around July sketched a genealogical branching of a single evolutionary tree, discarding Lamarck's independent lineages progressing to higher forms. Unconventionally, Darwin asked questions of fancy pigeon and animal breeders as well as established scientists. At the zoo he had his first sight of an ape, and was profoundly impressed by how human the orangutan seemed.


In late September 1838, he started reading Thomas Malthus's An Essay on the Principle of Population with its statistical argument that human populations, if unrestrained, breed beyond their means and struggle to survive. Darwin related this to the struggle for existence among wildlife and botanist de Candolle's "warring of the species" in plants; he immediately envisioned "a force like a hundred thousand wedges" pushing well-adapted variations into "gaps in the economy of nature", so that the survivors would pass on their form and abilities, and unfavourable variations would be destroyed. By December 1838, he had noted a similarity between the act of breeders selecting traits and a Malthusian Nature selecting among variants thrown up by "chance" so that "every part of newly acquired structure is fully practical and perfected".


Darwin continued to research and extensively revise his theory while focusing on his main work of publishing the scientific results of the Beagle voyage. He tentatively wrote of his ideas to Lyell in January 1842; then in June he roughed out a 35-page "Pencil Sketch" of his theory. Darwin began correspondence about his theorising with the botanist Joseph Dalton Hooker in January 1844, and by July had rounded out his "sketch" into a 230-page "Essay", to be expanded with his research results and published if he died prematurely.


In November 1844, the anonymously published popular science book Vestiges of the Natural History of Creation, written by Scottish journalist Robert Chambers, widened public interest in the concept of transmutation of species. Vestiges used evidence from the fossil record and embryology to support the claim that living things had progressed from the simple to the more complex over time. But it proposed a linear progression rather than the branching common descent theory behind Darwin's work in progress, and it ignored adaptation. Darwin read it soon after publication, and scorned its amateurish geology and zoology, but he carefully reviewed his own arguments after leading scientists, including Adam Sedgwick, attacked its morality and scientific errors. Vestiges had significant influence on public opinion, and the intense debate helped to pave the way for the acceptance of the more scientifically sophisticated Origin by moving evolutionary speculation into the mainstream. While few naturalists were willing to consider transmutation, Herbert Spencer became an active proponent of Lamarckism and progressive development in the 1850s.


Darwin's barnacle studies convinced him that variation arose constantly and not just in response to changed circumstances. In 1854, he completed the last part of his Beagle-related writing and began working full-time on evolution. His thinking changed from the view that species formed in isolated populations only, as on islands, to an emphasis on speciation without isolation; that is, he saw increasing specialisation within large stable populations as continuously exploiting new ecological niches. He conducted empirical research focusing on difficulties with his theory. He studied the developmental and anatomical differences between different breeds of many domestic animals, became actively involved in fancy pigeon breeding, and experimented (with the help of his son Francis) on ways that plant seeds and animals might disperse across oceans to colonise distant islands. By 1856, his theory was much more sophisticated, with a mass of supporting evidence.


An 1855 paper on the "introduction" of species, written by Alfred Russel Wallace, claimed that patterns in the geographical distribution of living and fossil species could be explained if every new species always came into existence near an already existing, closely related species. Charles Lyell recognised the implications of Wallace's paper and its possible connection to Darwin's work, although Darwin did not, and in a letter written on 1–2 May 1856 Lyell urged Darwin to publish his theory to establish priority. Darwin was torn between the desire to set out a full and convincing account and the pressure to quickly produce a short paper. He met Lyell, and in correspondence with Joseph Dalton Hooker affirmed that he did not want to expose his ideas to review by an editor as would have been required to publish in an academic journal. He began a "sketch" account on 14 May 1856, and by July had decided to produce a full technical treatise on species. His theory including the principle of divergence was complete by 5 September 1857 when he sent Asa Gray a brief but detailed abstract of his ideas.


Darwin was hard at work on his "big book" on Natural Selection, when on 18 June 1858 he received a parcel from Wallace, who stayed on the Maluku Islands (Ternate and Gilolo). It enclosed twenty pages describing an evolutionary mechanism, a response to Darwin's recent encouragement, with a request to send it on to Lyell if Darwin thought it worthwhile. The mechanism was similar to Darwin's own theory. Darwin wrote to Lyell that "your words have come true with a vengeance, ... forestalled" and he would "of course, at once write and offer to send [it] to any journal" that Wallace chose, adding that "all my originality, whatever it may amount to, will be smashed". Lyell and Hooker agreed that a joint publication putting together Wallace's pages with extracts from Darwin's 1844 Essay and his 1857 letter to Gray should be presented at the Linnean Society, and on 1 July 1858, the papers entitled On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection, by Wallace and Darwin respectively, were read out but drew little reaction. While Darwin considered Wallace's idea to be identical to his concept of natural selection, historians have pointed out differences. Darwin described natural selection as being analogous to the artificial selection practised by animal breeders, and emphasised competition between individuals; Wallace drew no comparison to selective breeding, and focused on ecological pressures that kept different varieties adapted to local conditions. Some historians have suggested that Wallace was actually discussing group selection rather than selection acting on individual variation.


After the meeting, Darwin decided to write "an abstract of my whole work". He started work on 20 July 1858, while on holiday at Sandown, and wrote parts of it from memory. Lyell discussed arrangements with publisher John Murray III, of the publishing house John Murray, who responded immediately to Darwin's letter of 31 March 1859 with an agreement to publish the book without even seeing the manuscript, and an offer to Darwin of 2⁄3 of the profits. (eventually Murray paid £180 to Darwin for the 1st edition and by Darwin's death in 1882 the book was in its 6th edition, earning Darwin nearly £3000.)


Darwin had initially decided to call his book An abstract of an Essay on the Origin of Species and Varieties Through natural selection, but with Murray's persuasion it was eventually changed to the snappier title: On the Origin of Species, with the title page adding by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life. Here the term "races" is used as an alternative for "varieties" and does not carry the modern connotation of human races—the first use in the book refers to "the several races, for instance, of the cabbage" and proceeds to a discussion of "the hereditary varieties or races of our domestic animals and plants".


Darwin had his basic theory of natural selection "by which to work" by December 1838, yet almost twenty years later, when Wallace's letter arrived on 18 June 1858, Darwin was still not ready to publish his theory. It was long thought that Darwin avoided or delayed making his ideas public for personal reasons. Reasons suggested have included fear of religious persecution or social disgrace if his views were revealed, and concern about upsetting his clergymen naturalist friends or his pious wife Emma. Charles Darwin's illness caused repeated delays. His paper on Glen Roy had proved embarrassingly wrong, and he may have wanted to be sure he was correct. David Quammen has suggested all these factors may have contributed, and notes Darwin's large output of books and busy family life during that time.


A more recent study by science historian John van Wyhe has determined that the idea that Darwin delayed publication only dates back to the 1940s, and Darwin's contemporaries thought the time he took was reasonable. Darwin always finished one book before starting another. While he was researching, he told many people about his interest in transmutation without causing outrage. He firmly intended to publish, but it was not until September 1854 that he could work on it full-time. His estimate that writing his "big book" would take five years was optimistic.


On the Origin of Species was first published on Thursday 24 November 1859, priced at fifteen shillings with a first printing of 1250 copies. The book had been offered to booksellers at Murray's autumn sale on Tuesday 22 November, and all available copies had been taken up immediately. In total, 1,250 copies were printed but after deducting presentation and review copies, and five for Stationers' Hall copyright, around 1,170 copies were available for sale. Significantly, 500 were taken by Mudie's Library, ensuring that the book promptly reached a large number of subscribers to the library. The second edition of 3,000 copies was quickly brought out on 7 January 1860, and incorporated numerous corrections as well as a response to religious objections by the addition of a new epigraph on page ii, a quotation from Charles Kingsley, and the phrase "by the Creator" added to the closing sentence. During Darwin's lifetime the book went through six editions, with cumulative changes and revisions to deal with counter-arguments raised. The third edition came out in 1861, with a number of sentences rewritten or added and an introductory appendix, An Historical Sketch of the Recent Progress of Opinion on the Origin of Species, while the fourth in 1866 had further revisions. The fifth edition, published on 10 February 1869, incorporated more changes and for the first time included the phrase "survival of the fittest", which had been coined by the philosopher Herbert Spencer in his Principles of Biology (1864).


In January 1871, George Jackson Mivart's On the Genesis of Species listed detailed arguments against natural selection, and claimed it included false metaphysics. Darwin made extensive revisions to the sixth edition of the Origin (this was the first edition in which he used the word "evolution" which had commonly been associated with embryological development, though all editions concluded with the word "evolved"), and added a new chapter VII, Miscellaneous objections, to address Mivart's arguments.


In the United States, botanist Asa Gray an American colleague of Darwin negotiated with a Boston publisher for publication of an authorised American version, but learnt that two New York publishing firms were already planning to exploit the absence of international copyright to print Origin. Darwin was delighted by the popularity of the book, and asked Gray to keep any profits. Gray managed to negotiate a 5% royalty with Appleton's of New York, who got their edition out in mid January 1860, and the other two withdrew. In a May letter, Darwin mentioned a print run of 2,500 copies, but it is not clear if this referred to the first printing only as there were four that year.


The book was widely translated in Darwin's lifetime, but problems arose with translating concepts and metaphors, and some translations were biased by the translator's own agenda. Darwin distributed presentation copies in France and Germany, hoping that suitable applicants would come forward, as translators were expected to make their own arrangements with a local publisher. He welcomed the distinguished elderly naturalist and geologist Heinrich Georg Bronn, but the German translation published in 1860 imposed Bronn's own ideas, adding controversial themes that Darwin had deliberately omitted. Bronn translated "favoured races" as "perfected races", and added essays on issues including the origin of life, as well as a final chapter on religious implications partly inspired by Bronn's adherence to Naturphilosophie. In 1862, Bronn produced a second edition based on the third English edition and Darwin's suggested additions, but then died of a heart attack. Darwin corresponded closely with Julius Victor Carus, who published an improved translation in 1867. Darwin's attempts to find a translator in France fell through, and the translation by Clémence Royer published in 1862 added an introduction praising Darwin's ideas as an alternative to religious revelation and promoting ideas anticipating social Darwinism and eugenics, as well as numerous explanatory notes giving her own answers to doubts that Darwin expressed. Darwin corresponded with Royer about a second edition published in 1866 and a third in 1870, but he had difficulty getting her to remove her notes and was troubled by these editions. He remained unsatisfied until a translation by Edmond Barbier was published in 1876. A Dutch translation by Tiberius Cornelis Winkler was published in 1860. By 1864, additional translations had appeared in Italian and Russian. In Darwin's lifetime, Origin was published in Swedish in 1871, Danish in 1872, Polish in 1873, Hungarian in 1873–1874, Spanish in 1877 and Serbian in 1878. By 1977, it had appeared in an additional 18 languages.


Page ii contains quotations by William Whewell and Francis Bacon on the theology of natural laws, harmonising science and religion in accordance with Isaac Newton's belief in a rational God who established a law-abiding cosmos. In the second edition, Darwin added an epigraph from Joseph Butler affirming that God could work through scientific laws as much as through miracles, in a nod to the religious concerns of his oldest friends. The Introduction establishes Darwin's credentials as a naturalist and author, then refers to John Herschel's letter suggesting that the origin of species "would be found to be a natural in contradistinction to a miraculous process":


Chapter I covers animal husbandry and plant breeding, going back to ancient Egypt. Darwin discusses contemporary opinions on the origins of different breeds under cultivation to argue that many have been produced from common ancestors by selective breeding. As an illustration of artificial selection, he describes fancy pigeon breeding, noting that "[t]he diversity of the breeds is something astonishing", yet all were descended from one species of rock pigeon. Darwin saw two distinct kinds of variation: (1) rare abrupt changes he called "sports" or "monstrosities" (example: ancon sheep with short legs), and (2) ubiquitous small differences (example: slightly shorter or longer bill of pigeons). Both types of hereditary changes can be used by breeders. However, for Darwin the small changes were most important in evolution.


In Chapter II, Darwin specifies that the distinction between species and varieties is arbitrary, with experts disagreeing and changing their decisions when new forms were found. He concludes that "a well-marked variety may be justly called an incipient species" and that "species are only strongly marked and permanent varieties". He argues for the ubiquity of variation in nature. Historians have noted that naturalists had long been aware that the individuals of a species differed from one another, but had generally considered such variations to be limited and unimportant deviations from the archetype of each species, that archetype being a fixed ideal in the mind of God. Darwin and Wallace made variation among individuals of the same species central to understanding the natural world.


He notes that both A. P. de Candolle and Charles Lyell had stated that all organisms are exposed to severe competition. Darwin emphasizes that he used the phrase "struggle for existence" in "a large and metaphorical sense, including dependence of one being on another"; he gives examples ranging from plants struggling against drought to plants competing for birds to eat their fruit and disseminate their seeds. He describes the struggle resulting from population growth: "It is the doctrine of Malthus applied with manifold force to the whole animal and vegetable kingdoms." He discusses checks to such increase including complex ecological interdependencies, and notes that competition is most severe between closely related forms "which fill nearly the same place in the economy of nature".


Chapter IV details natural selection under the "infinitely complex and close-fitting ... mutual relations of all organic beings to each other and to their physical conditions of life". Darwin takes as an example a country where a change in conditions led to extinction of some species, immigration of others and, where suitable variations occurred, descendants of some species became adapted to new conditions. He remarks that the artificial selection practised by animal breeders frequently produced sharp divergence in character between breeds, and suggests that natural selection might do the same, saying:


Darwin proposes sexual selection, driven by competition between males for mates, to explain sexually dimorphic features such as lion manes, deer antlers, peacock tails, bird songs, and the bright plumage of some male birds. He analysed sexual selection more fully in The Descent of Man, and Selection in Relation to Sex (1871). Natural selection was expected to work very slowly in forming new species, but given the effectiveness of artificial selection, he could "see no limit to the amount of change, to the beauty and infinite complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may be effected in the long course of time by nature's power of selection". Using a tree diagram and calculations, he indicates the "divergence of character" from original species into new species and genera. He describes branches falling off as extinction occurred, while new branches formed in "the great Tree of life ... with its ever branching and beautiful ramifications".


In Darwin's time there was no agreed-upon model of heredity; in Chapter I Darwin admitted, "The laws governing inheritance are quite unknown." He accepted a version of the inheritance of acquired characteristics (which after Darwin's death came to be called Lamarckism), and Chapter V discusses what he called the effects of use and disuse; he wrote that he thought "there can be little doubt that use in our domestic animals strengthens and enlarges certain parts, and disuse diminishes them; and that such modifications are inherited", and that this also applied in nature. Darwin stated that some changes that were commonly attributed to use and disuse, such as the loss of functional wings in some island dwelling insects, might be produced by natural selection. In later editions of Origin, Darwin expanded the role attributed to the inheritance of acquired characteristics. Darwin also admitted ignorance of the source of inheritable variations, but speculated they might be produced by environmental factors. However, one thing was clear: whatever the exact nature and causes of new variations, Darwin knew from observation and experiment that breeders were able to select such variations and produce huge differences in many generations of selection. The observation that selection works in domestic animals is not destroyed by lack of understanding of the underlying hereditary mechanism.


More detail was given in Darwin's 1868 book on The Variation of Animals and Plants under Domestication, which tried to explain heredity through his hypothesis of pangenesis. Although Darwin had privately questioned blending inheritance, he struggled with the theoretical difficulty that novel individual variations would tend to blend into a population. However, inherited variation could be seen, and Darwin's concept of selection working on a population with a range of small variations was workable. It was not until the modern evolutionary synthesis in the 1930s and 1940s that a model of heredity became completely integrated with a model of variation. This modern evolutionary synthesis had been dubbed Neo Darwinian Evolution because it encompasses Charles Darwin's theories of evolution with Gregor Mendel's theories of genetic inheritance.


Chapter VI begins by saying the next three chapters will address possible objections to the theory, the first being that often no intermediate forms between closely related species are found, though the theory implies such forms must have existed. As Darwin noted, "Firstly, why, if species have descended from other species by insensibly fine gradations, do we not everywhere see innumerable transitional forms? Why is not all nature in confusion, instead of the species being, as we see them, well defined?" Darwin attributed this to the competition between different forms, combined with the small number of individuals of intermediate forms, often leading to extinction of such forms. This difficulty can be referred to as the absence or rarity of transitional varieties in habitat space.


His answer was that in many cases animals exist with intermediate structures that are functional. He presented flying squirrels, and flying lemurs as examples of how bats might have evolved from non-flying ancestors. He discussed various simple eyes found in invertebrates, starting with nothing more than an optic nerve coated with pigment, as examples of how the vertebrate eye could have evolved. Darwin concludes: "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case."


Chapter VII (of the first edition) addresses the evolution of instincts. His examples included two he had investigated experimentally: slave-making ants and the construction of hexagonal cells by honey bees. Darwin noted that some species of slave-making ants were more dependent on slaves than others, and he observed that many ant species will collect and store the pupae of other species as food. He thought it reasonable that species with an extreme dependency on slave workers had evolved in incremental steps. He suggested that bees that make hexagonal cells evolved in steps from bees that made round cells, under pressure from natural selection to economise wax. Darwin concluded:


Chapter VIII addresses the idea that species had special characteristics that prevented hybrids from being fertile in order to preserve separately created species. Darwin said that, far from being constant, the difficulty in producing hybrids of related species, and the viability and fertility of the hybrids, varied greatly, especially among plants. Sometimes what were widely considered to be separate species produced fertile hybrid offspring freely, and in other cases what were considered to be mere varieties of the same species could only be crossed with difficulty. Darwin concluded: "Finally, then, the facts briefly given in this chapter do not seem to me opposed to, but even rather to support the view, that there is no fundamental distinction between species and varieties."


In the sixth edition Darwin inserted a new chapter VII (renumbering the subsequent chapters) to respond to criticisms of earlier editions, including the objection that many features of organisms were not adaptive and could not have been produced by natural selection. He said some such features could have been by-products of adaptive changes to other features, and that often features seemed non-adaptive because their function was unknown, as shown by his book on Fertilisation of Orchids that explained how their elaborate structures facilitated pollination by insects. Much of the chapter responds to George Jackson Mivart's criticisms, including his claim that features such as baleen filters in whales, flatfish with both eyes on one side and the camouflage of stick insects could not have evolved through natural selection because intermediate stages would not have been adaptive. Darwin proposed scenarios for the incremental evolution of each feature.


Chapter IX deals with the fact that the geologic record appears to show forms of life suddenly arising, without the innumerable transitional fossils expected from gradual changes. Darwin borrowed Charles Lyell's argument in Principles of Geology that the record is extremely imperfect as fossilisation is a very rare occurrence, spread over vast periods of time; since few areas had been geologically explored, there could only be fragmentary knowledge of geological formations, and fossil collections were very poor. Evolved local varieties which migrated into a wider area would seem to be the sudden appearance of a new species. Darwin did not expect to be able to reconstruct evolutionary history, but continuing discoveries gave him well founded hope that new finds would occasionally reveal transitional forms. To show that there had been enough time for natural selection to work slowly, he again cited Principles of Geology and other observations based on sedimentation and erosion, including an estimate that erosion of The Weald had taken 300 million years. The initial appearance of entire groups of well developed organisms in the oldest fossil-bearing layers, now known as the Cambrian explosion, posed a problem. Darwin had no doubt that earlier seas had swarmed with living creatures, but stated that he had no satisfactory explanation for the lack of fossils. Fossil evidence of pre-Cambrian life has since been found, extending the history of life back for billions of years.


Chapter X examines whether patterns in the fossil record are better explained by common descent and branching evolution through natural selection, than by the individual creation of fixed species. Darwin expected species to change slowly, but not at the same rate – some organisms such as Lingula were unchanged since the earliest fossils. The pace of natural selection would depend on variability and change in the environment. This distanced his theory from Lamarckian laws of inevitable progress. It has been argued that this anticipated the punctuated equilibrium hypothesis, but other scholars have preferred to emphasise Darwin's commitment to gradualism. He cited Richard Owen's findings that the earliest members of a class were a few simple and generalised species with characteristics intermediate between modern forms, and were followed by increasingly diverse and specialised forms, matching the branching of common descent from an ancestor. Patterns of extinction matched his theory, with related groups of species having a continued existence until extinction, then not reappearing. Recently extinct species were more similar to living species than those from earlier eras, and as he had seen in South America, and William Clift had shown in Australia, fossils from recent geological periods resembled species still living in the same area.


Chapter XI deals with evidence from biogeography, starting with the observation that differences in flora and fauna from separate regions cannot be explained by environmental differences alone; South America, Africa, and Australia all have regions with similar climates at similar latitudes, but those regions have very different plants and animals. The species found in one area of a continent are more closely allied with species found in other regions of that same continent than to species found on other continents. Darwin noted that barriers to migration played an important role in the differences between the species of different regions. The coastal sea life of the Atlantic and Pacific sides of Central America had almost no species in common even though the Isthmus of Panama was only a few miles wide. His explanation was a combination of migration and descent with modification. He went on to say: "On this principle of inheritance with modification, we can understand how it is that sections of genera, whole genera, and even families are confined to the same areas, as is so commonly and notoriously the case." Darwin explained how a volcanic island formed a few hundred miles from a continent might be colonised by a few species from that continent. These species would become modified over time, but would still be related to species found on the continent, and Darwin observed that this was a common pattern. Darwin discussed ways that species could be dispersed across oceans to colonise islands, many of which he had investigated experimentally.


Darwin discusses morphology, including the importance of homologous structures. He says, "What can be more curious than that the hand of a man, formed for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and the wing of the bat, should all be constructed on the same pattern, and should include the same bones, in the same relative positions?" He notes that animals of the same class often have extremely similar embryos. Darwin discusses rudimentary organs, such as the wings of flightless birds and the rudiments of pelvis and leg bones found in some snakes. He remarks that some rudimentary organs, such as teeth in baleen whales, are found only in embryonic stages.


The final chapter reviews points from earlier chapters, and Darwin concludes by hoping that his theory might produce revolutionary changes in many fields of natural history. Although he avoids the controversial topic of human origins in the rest of the book so as not to prejudice readers against his theory, here he ventures a cautious hint that psychology would be put on a new foundation and that "Light will be thrown on the origin of man". Darwin ends with a passage that became well known and much quoted:


Darwin's aims were twofold: to show that species had not been separately created, and to show that natural selection had been the chief agent of change. He knew that his readers were already familiar with the concept of transmutation of species from Vestiges, and his introduction ridicules that work as failing to provide a viable mechanism. Therefore, the first four chapters lay out his case that selection in nature, caused by the struggle for existence, is analogous to the selection of variations under domestication, and that the accumulation of adaptive variations provides a scientifically testable mechanism for evolutionary speciation.


Later chapters provide evidence that evolution has occurred, supporting the idea of branching, adaptive evolution without directly proving that selection is the mechanism. Darwin presents supporting facts drawn from many disciplines, showing that his theory could explain a myriad of observations from many fields of natural history that were inexplicable under the alternate concept that species had been individually created. The structure of Darwin's argument showed the influence of John Herschel, whose philosophy of science maintained that a mechanism could be called a vera causa (true cause) if three things could be demonstrated: its existence in nature, its ability to produce the effects of interest, and its ability to explain a wide range of observations.


While the book was readable enough to sell, its dryness ensured that it was seen as aimed at specialist scientists and could not be dismissed as mere journalism or imaginative fiction. Unlike the still-popular Vestiges, it avoided the narrative style of the historical novel and cosmological speculation, though the closing sentence clearly hinted at cosmic progression. Darwin had long been immersed in the literary forms and practices of specialist science, and made effective use of his skills in structuring arguments. David Quammen has described the book as written in everyday language for a wide audience, but noted that Darwin's literary style was uneven: in some places he used convoluted sentences that are difficult to read, while in other places his writing was beautiful. Quammen advised that later editions were weakened by Darwin making concessions and adding details to address his critics, and recommended the first edition. James T. Costa said that because the book was an abstract produced in haste in response to Wallace's essay, it was more approachable than the big book on natural selection Darwin had been working on, which would have been encumbered by scholarly footnotes and much more technical detail. He added that some parts of Origin are dense, but other parts are almost lyrical, and the case studies and observations are presented in a narrative style unusual in serious scientific books, which broadened its audience.


The book aroused international interest and a widespread debate, with no sharp line between scientific issues and ideological, social and religious implications. Much of the initial reaction was hostile, but Darwin had to be taken seriously as a prominent and respected name in science. There was much less controversy than had greeted the 1844 publication Vestiges of Creation, which had been rejected by scientists, but had influenced a wide public readership into believing that nature and human society were governed by natural laws. The Origin of Species as a book of wide general interest became associated with ideas of social reform. Its proponents made full use of a surge in the publication of review journals, and it was given more popular attention than almost any other scientific work, though it failed to match the continuing sales of Vestiges. Darwin's book legitimised scientific discussion of evolutionary mechanisms, and the newly coined term Darwinism was used to cover the whole range of evolutionism, not just his own ideas. By the mid-1870s, evolutionism was triumphant.


Scientific readers were already aware of arguments that species changed through processes that were subject to laws of nature, but the transmutational ideas of Lamarck and the vague "law of development" of Vestiges had not found scientific favour. Darwin presented natural selection as a scientifically testable mechanism while accepting that other mechanisms such as inheritance of acquired characters were possible. His strategy established that evolution through natural laws was worthy of scientific study, and by 1875, most scientists accepted that evolution occurred but few thought natural selection was significant. Darwin's scientific method was also disputed, with his proponents favouring the empiricism of John Stuart Mill's A System of Logic, while opponents held to the idealist school of William Whewell's Philosophy of the Inductive Sciences, in which investigation could begin with the intuitive truth that species were fixed objects created by design. Early support for Darwin's ideas came from the findings of field naturalists studying biogeography and ecology, including Joseph Dalton Hooker in 1860, and Asa Gray in 1862. Henry Walter Bates presented research in 1861 that explained insect mimicry using natural selection. Alfred Russel Wallace discussed evidence from his Malay archipelago research, including an 1864 paper with an evolutionary explanation for the Wallace line.


Evolution had less obvious applications to anatomy and morphology, and at first had little impact on the research of the anatomist Thomas Henry Huxley. Despite this, Huxley strongly supported Darwin on evolution; though he called for experiments to show whether natural selection could form new species, and questioned if Darwin's gradualism was sufficient without sudden leaps to cause speciation. Huxley wanted science to be secular, without religious interference, and his article in the April 1860 Westminster Review promoted scientific naturalism over natural theology, praising Darwin for "extending the domination of Science over regions of thought into which she has, as yet, hardly penetrated" and coining the term "Darwinism" as part of his efforts to secularise and professionalise science. Huxley gained influence, and initiated the X Club, which used the journal Nature to promote evolution and naturalism, shaping much of late Victorian science. Later, the German morphologist Ernst Haeckel would convince Huxley that comparative anatomy and palaeontology could be used to reconstruct evolutionary genealogies.


The leading naturalist in Britain was the anatomist Richard Owen, an idealist who had shifted to the view in the 1850s that the history of life was the gradual unfolding of a divine plan. Owen's review of the Origin in the April 1860 Edinburgh Review bitterly attacked Huxley, Hooker and Darwin, but also signalled acceptance of a kind of evolution as a teleological plan in a continuous "ordained becoming", with new species appearing by natural birth. Others that rejected natural selection, but supported "creation by birth", included the Duke of Argyll who explained beauty in plumage by design. Since 1858, Huxley had emphasised anatomical similarities between apes and humans, contesting Owen's view that humans were a separate sub-class. Their disagreement over human origins came to the fore at the British Association for the Advancement of Science meeting featuring the legendary 1860 Oxford evolution debate. In two years of acrimonious public dispute that Charles Kingsley satirised as the "Great Hippocampus Question" and parodied in The Water-Babies as the "great hippopotamus test", Huxley showed that Owen was incorrect in asserting that ape brains lacked a structure present in human brains. Others, including Charles Lyell and Alfred Russel Wallace, thought that humans shared a common ancestor with apes, but higher mental faculties could not have evolved through a purely material process. Darwin published his own explanation in the Descent of Man (1871).


Evolutionary ideas, although not natural selection, were accepted by German biologists accustomed to ideas of homology in morphology from Goethe's Metamorphosis of Plants and from their long tradition of comparative anatomy. Bronn's alterations in his German translation added to the misgivings of conservatives, but enthused political radicals. Ernst Haeckel was particularly ardent, aiming to synthesise Darwin's ideas with those of Lamarck and Goethe while still reflecting the spirit of Naturphilosophie. Their ambitious programme to reconstruct the evolutionary history of life was joined by Huxley and supported by discoveries in palaeontology. Haeckel used embryology extensively in his recapitulation theory, which embodied a progressive, almost linear model of evolution. Darwin was cautious about such histories, and had already noted that von Baer's laws of embryology supported his idea of complex branching.


French-speaking naturalists in several countries showed appreciation of the much modified French translation by Clémence Royer, but Darwin's ideas had little impact in France, where any scientists supporting evolutionary ideas opted for a form of Lamarckism. The intelligentsia in Russia had accepted the general phenomenon of evolution for several years before Darwin had published his theory, and scientists were quick to take it into account, although the Malthusian aspects were felt to be relatively unimportant. The political economy of struggle was criticised as a British stereotype by Karl Marx and by Leo Tolstoy, who had the character Levin in his novel Anna Karenina voice sharp criticism of the morality of Darwin's views.


There were serious scientific objections to the process of natural selection as the key mechanism of evolution, including Karl von Nägeli's insistence that a trivial characteristic with no adaptive advantage could not be developed by selection. Darwin conceded that these could be linked to adaptive characteristics. His estimate that the age of the Earth allowed gradual evolution was disputed by William Thomson (later awarded the title Lord Kelvin), who calculated that it had cooled in less than 100 million years. Darwin accepted blending inheritance, but Fleeming Jenkin calculated that as it mixed traits, natural selection could not accumulate useful traits. Darwin tried to meet these objections in the 5th edition. Mivart supported directed evolution, and compiled scientific and religious objections to natural selection. In response, Darwin made considerable changes to the sixth edition. The problems of the age of the Earth and heredity were only resolved in the 20th century.


By the mid-1870s, most scientists accepted evolution, but relegated natural selection to a minor role as they believed evolution was purposeful and progressive. The range of evolutionary theories during "the eclipse of Darwinism" included forms of "saltationism" in which new species were thought to arise through "jumps" rather than gradual adaptation, forms of orthogenesis claiming that species had an inherent tendency to change in a particular direction, and forms of neo-Lamarckism in which inheritance of acquired characteristics led to progress. The minority view of August Weismann, that natural selection was the only mechanism, was called neo-Darwinism. It was thought that the rediscovery of Mendelian inheritance invalidated Darwin's views.


While some, like Spencer, used analogy from natural selection as an argument against government intervention in the economy to benefit the poor, others, including Alfred Russel Wallace, argued that action was needed to correct social and economic inequities to level the playing field before natural selection could improve humanity further. Some political commentaries, including Walter Bagehot's Physics and Politics (1872), attempted to extend the idea of natural selection to competition between nations and between human races. Such ideas were incorporated into what was already an ongoing effort by some working in anthropology to provide scientific evidence for the superiority of Caucasians over non white races and justify European imperialism. Historians write that most such political and economic commentators had only a superficial understanding of Darwin's scientific theory, and were as strongly influenced by other concepts about social progress and evolution, such as the Lamarckian ideas of Spencer and Haeckel, as they were by Darwin's work. Darwin objected to his ideas being used to justify military aggression and unethical business practices as he believed morality was part of fitness in humans, and he opposed polygenism, the idea that human races were fundamentally distinct and did not share a recent common ancestry.


Natural theology was not a unified doctrine, and while some such as Louis Agassiz were strongly opposed to the ideas in the book, others sought a reconciliation in which evolution was seen as purposeful. In the Church of England, some liberal clergymen interpreted natural selection as an instrument of God's design, with the cleric Charles Kingsley seeing it as "just as noble a conception of Deity". In the second edition of January 1860, Darwin quoted Kingsley as "a celebrated cleric", and added the phrase "by the Creator" to the closing sentence, which from then on read "life, with its several powers, having been originally breathed by the Creator into a few forms or into one". While some commentators have taken this as a concession to religion that Darwin later regretted, Darwin's view at the time was of God creating life through the laws of nature, and even in the first edition there are several references to "creation".


Baden Powell praised "Mr Darwin's masterly volume [supporting] the grand principle of the self-evolving powers of nature". In America, Asa Gray argued that evolution is the secondary effect, or modus operandi, of the first cause, design, and published a pamphlet defending the book in terms of theistic evolution, Natural Selection is not inconsistent with Natural Theology. Theistic evolution became a popular compromise, and St. George Jackson Mivart was among those accepting evolution but attacking Darwin's naturalistic mechanism. Eventually it was realised that supernatural intervention could not be a scientific explanation, and naturalistic mechanisms such as neo-Lamarckism were favoured over natural selection as being more compatible with purpose.


Even though the book had barely hinted at human evolution, it quickly became central to the debate as mental and moral qualities were seen as spiritual aspects of the immaterial soul, and it was believed that animals did not have spiritual qualities. This conflict could be reconciled by supposing there was some supernatural intervention on the path leading to humans, or viewing evolution as a purposeful and progressive ascent to mankind's position at the head of nature. While many conservative theologians accepted evolution, Charles Hodge argued in his 1874 critique "What is Darwinism?" that "Darwinism", defined narrowly as including rejection of design, was atheism though he accepted that Asa Gray did not reject design. Asa Gray responded that this charge misrepresented Darwin's text. By the early 20th century, four noted authors of The Fundamentals were explicitly open to the possibility that God created through evolution, but fundamentalism inspired the American creation–evolution controversy that began in the 1920s. Some conservative Roman Catholic writers and influential Jesuits opposed evolution in the late 19th and early 20th century, but other Catholic writers, starting with Mivart, pointed out that early Church Fathers had not interpreted Genesis literally in this area. The Vatican stated its official position in a 1950 papal encyclical, which held that evolution was not inconsistent with Catholic teaching.


Modern evolutionary theory continues to develop. Darwin's theory of evolution by natural selection, with its tree-like model of branching common descent, has become the unifying theory of the life sciences. The theory explains the diversity of living organisms and their adaptation to the environment. It makes sense of the geologic record, biogeography, parallels in embryonic development, biological homologies, vestigiality, cladistics, phylogenetics and other fields, with unrivalled explanatory power; it has also become essential to applied sciences such as medicine and agriculture. Despite the scientific consensus, a religion-based political controversy has developed over how evolution is taught in schools, especially in the United States.


Interest in Darwin's writings continues, and scholars have generated an extensive literature, the Darwin Industry, about his life and work. The text of Origin itself has been subject to much analysis including a variorum, detailing the changes made in every edition, first published in 1959, and a concordance, an exhaustive external index published in 1981. Worldwide commemorations of the 150th anniversary of the publication of On the Origin of Species and the bicentenary of Darwin's birth were scheduled for 2009. They celebrated the ideas which "over the last 150 years have revolutionised our understanding of nature and our place within it".


The dissolution of the Soviet Union was formally enacted on December 26, 1991, as a result of the declaration no. 142-Н of the Soviet of the Republics of the Supreme Soviet of the Soviet Union. The declaration acknowledged the independence of the former Soviet republics and created the Commonwealth of Independent States (CIS), although five of the signatories ratified it much later or not at all. On the previous day, Soviet President Mikhail Gorbachev, the eighth and last leader of the Soviet Union, resigned, declared his office extinct, and handed over its powers – including control of the Soviet nuclear missile launching codes – to Russian President Boris Yeltsin. That evening at 7:32 p.m., the Soviet flag was lowered from the Kremlin for the last time and replaced with the pre-revolutionary Russian flag.


Mikhail Gorbachev was elected General Secretary by the Politburo on March 11, 1985, three hours after predecessor Konstantin Chernenko's death at age 73. Gorbachev, aged 54, was the youngest member of the Politburo. His initial goal as general secretary was to revive the Soviet economy, and he realized that doing so would require reforming underlying political and social structures. The reforms began with personnel changes of senior Brezhnev-era officials who would impede political and economic change. On April 23, 1985, Gorbachev brought two protégés, Yegor Ligachev and Nikolai Ryzhkov, into the Politburo as full members. He kept the "power" ministries happy by promoting KGB Head Viktor Chebrikov from candidate to full member and appointing Minister of Defence Marshal Sergei Sokolov as a Politburo candidate.


This liberalization, however, fostered nationalist movements and ethnic disputes within the Soviet Union. It also led indirectly to the revolutions of 1989, in which Soviet-imposed communist regimes of the Warsaw Pact were peacefully toppled (Romania excepted), which in turn increased pressure on Gorbachev to introduce greater democracy and autonomy for the Soviet Union's constituent republics. Under Gorbachev's leadership, the Communist Party of the Soviet Union in 1989 introduced limited competitive elections to a new central legislature, the Congress of People's Deputies (although the ban on other political parties was not lifted until 1990).


In May 1985, Gorbachev delivered a speech in Leningrad advocating reforms and an anti-alcohol campaign to tackle widespread alcoholism. Prices on vodka, wine, and beer were raised in order to make these drinks more expensive and a disincentive to consumers, and the introduction of rationing. Unlike most forms of rationing intended to conserve scarce goods, this was done to restrict sales with the overt goal of curtailing drunkenness. Gorbachev's plan also included billboards promoting sobriety, increased penalties for public drunkenness, and to censor drinking scenes from old movies. Although this program was not a direct copycat of Tsar Nicholas II's outright prohibition during World War I, Gorbachev faced the same adverse economic reaction as did the last Tsar. The disincentivization of alcohol consumption was a serious blow to the state budget according to Alexander Yakovlev, who noted annual collections of alcohol taxes decreased by 100 billion rubles. Alcohol production migrated to the black market, or through moonshining as some made "bathtub vodka" with homegrown potatoes. Poorer, less educated Russians resorted to drinking unhealthy substitutes such as nail polish, rubbing alcohol or men's cologne, which only served to be an additional burden on Russia's healthcare sector due to the subsequent poisoning cases. The purpose of these reforms, however, was to prop up the existing centrally planned economy, unlike later reforms, which tended toward market socialism.


On July 1, 1985, Gorbachev promoted Eduard Shevardnadze, First Secretary of the Georgian Communist Party, to full member of the Politburo, and the following day appointed him minister of foreign affairs, replacing longtime Foreign Minister Andrei Gromyko. The latter, disparaged as "Mr Nyet" in the West, had served for 28 years as Minister of Foreign Affairs. Gromyko was relegated to the largely ceremonial position of Chairman of the Presidium of the Supreme Soviet (officially Soviet Head of State), as he was considered an "old thinker." Also on July 1, Gorbachev took the opportunity to dispose of his main rival by removing Grigory Romanov from the Politburo, and brought Boris Yeltsin and Lev Zaikov into the CPSU Central Committee Secretariat.


In the fall of 1985, Gorbachev continued to bring younger and more energetic men into government. On September 27, Nikolai Ryzhkov replaced 79-year-old Nikolai Tikhonov as Chairman of the Council of Ministers, effectively the Soviet prime minister, and on October 14, Nikolai Talyzin replaced Nikolai Baibakov as chairman of the State Planning Committee (GOSPLAN). At the next Central Committee meeting on October 15, Tikhonov retired from the Politburo and Talyzin became a candidate. Finally, on December 23, 1985, Gorbachev appointed Yeltsin First Secretary of the Moscow Communist Party replacing Viktor Grishin.


The CTAG (Latvian: Cilvēktiesību aizstāvības grupa, Human Rights Defense Group) Helsinki-86 was founded in July 1986 in the Latvian port town of Liepāja by three workers: Linards Grantiņš, Raimonds Bitenieks, and Mārtiņš Bariss. Its name refers to the human-rights statements of the Helsinki Accords. Helsinki-86 was the first openly anti-Communist organization in the U.S.S.R., and the first openly organized opposition to the Soviet regime, setting an example for other ethnic minorities' pro-independence movements.[citation needed]


The "Jeltoqsan" (Kazakh for "December") of 1986 were riots in Alma-Ata, Kazakhstan, sparked by Gorbachev's dismissal of Dinmukhamed Konayev, the First Secretary of the Communist Party of Kazakhstan and an ethnic Kazakh, who was replaced with Gennady Kolbin, an outsider from the Russian SFSR. Demonstrations started in the morning of December 17, 1986, with 200 to 300 students in front of the Central Committee building on Brezhnev Square protesting Konayev's dismissal and replacement by a Russian. Protesters swelled to 1,000 to 5,000 as other students joined the crowd. The CPK Central Committee ordered troops from the Ministry of Internal Affairs, druzhiniki (volunteers), cadets, policemen, and the KGB to cordon the square and videotape the participants. The situation escalated around 5 p.m., as troops were ordered to disperse the protesters. Clashes between the security forces and the demonstrators continued throughout the night in Almaty.


On the next day, December 18, protests turned into civil unrest as clashes between troops, volunteers, militia units, and Kazakh students turned into a wide-scale confrontation. The clashes could only be controlled on the third day. The Almaty events were followed by smaller protests and demonstrations in Shymkent, Pavlodar, Karaganda, and Taldykorgan. Reports from Kazakh SSR authorities estimated that the riots drew 3,000 people. Other estimates are of at least 30,000 to 40,000 protestors with 5,000 arrested and jailed, and an unknown number of casualties. Jeltoqsan leaders say over 60,000 Kazakhs participated in the protests. According to the Kazakh SSR government, there were two deaths during the riots, including a volunteer police worker and a student. Both of them had died due to blows to the head. About 100 others were detained and several others were sentenced to terms in labor camps. Sources cited by the Library of Congress claimed that at least 200 people died or were summarily executed soon thereafter; some accounts estimate casualties at more than 1,000. The writer Mukhtar Shakhanov claimed that a KGB officer testified that 168 protesters were killed, but that figure remains unconfirmed.


Gorbachev also radically expanded the scope of Glasnost, stating that no subject was off-limits for open discussion in the media. Even so, the cautious Soviet intelligentsia took almost a year to begin pushing the boundaries to see if he meant what he said. For the first time, the Communist Party leader had appealed over the heads of Central Committee members for the people's support in exchange for expansion of liberties. The tactic proved successful: Within two years political reform could no longer be sidetracked by Party "conservatives." An unintended consequence was that having saved reform, Gorbachev's move ultimately killed the very system it was designed to save.


On February 7, 1987, dozens of political prisoners were freed in the first group release since Khrushchev's "thaw" in the mid-1950s. On May 6, 1987, Pamyat, a Russian nationalist group, held an unsanctioned demonstration in Moscow. The authorities did not break up the demonstration and even kept traffic out of the demonstrators' way while they marched to an impromptu meeting with Boris Yeltsin, head of the Moscow Communist Party and at the time one of Gorbachev's closest allies. On July 25, 1987, 300 Crimean Tatars staged a noisy demonstration near the Kremlin Wall for several hours, calling for the right to return to their homeland, from which they were deported in 1944; police and soldiers merely looked on.


On September 10, 1987, after a lecture from hardliner Yegor Ligachev at the Politburo for allowing these two unsanctioned demonstrations in Moscow, Boris Yeltsin wrote a letter of resignation to Gorbachev, who had been holidaying on the Black Sea. Gorbachev was stunned – no one had ever voluntarily resigned from the Politburo. At the October 27, 1987, plenary meeting of the Central Committee, Yeltsin, frustrated that Gorbachev had not addressed any of the issues outlined in his resignation letter, criticized the slow pace of reform, servility to the general secretary, and opposition from Ligachev that had led to his (Yeltsin's) resignation. No one had ever addressed the Party leader so brazenly in front of the Central Committee since Leon Trotsky in the 1920s. In his reply, Gorbachev accused Yeltsin of "political immaturity" and "absolute irresponsibility." No one backed Yeltsin.


On June 14, 1987, about 5,000 people gathered again at Freedom Monument in Riga, and laid flowers to commemorate the anniversary of Stalin's mass deportation of Latvians in 1941. This was the first large demonstration in the Baltic republics to commemorate the anniversary of an event contrary to official Soviet history. The authorities did not crack down on demonstrators, which encouraged more and larger demonstrations throughout the Baltic States. The next major anniversary after the August 23 Molotov Pact demonstration was on November 18, the date of Latvia’s independence in 1918. On November 18, 1987, hundreds of police and civilian militiamen cordoned off the central square to prevent any demonstration at Freedom Monument, but thousands lined the streets of Riga in silent protest regardless.


In spring 1987, a protest movement arose against new phosphate mines in Estonia. Signatures were collected in Tartu, and students assembled in the university's main hall to express lack of confidence in the government. At a demonstration on May 1, 1987, young people showed up with banners and slogans despite an official ban. On August 15, 1987, former political prisoners formed the MRP-AEG group (Estonians for the Public Disclosure of the Molotov-Ribbentrop Pact), which was headed by Tiit Madisson. In September 1987, the Edasi newspaper published a proposal by Edgar Savisaar, Siim Kallas, Tiit Made, and Mikk Titma calling for Estonia's transition to autonomy. Initially geared toward economic independence, then toward a certain amount of political autonomy, the project, Isemajandav Eesti ("A Self-Managing Estonia") became known according to its Estonian acronym, IME, which means "miracle". On October 21, a demonstration dedicated to those who gave their lives in the 1918–1920 Estonian War of Independence took place in Võru, which culminated in a conflict with the militia. For the first time in years, the blue, black, and white national tricolor was publicly displayed.


On October 17, 1987, about 3,000 Armenians demonstrated in Yerevan complaining about the condition of Lake Sevan, the Nairit chemicals plant, and the Metsamor Nuclear Power Plant, and air pollution in Yerevan. Police tried to prevent the protest but took no action to stop it once the march was underway. The demonstration was led by Armenian writers such as Silva Kaputikian, Zori Balayan, and Maro Margarian and leaders from the National Survival organization. The march originated at the Opera Plaza after speakers, mainly intellectuals, addressed the crowd.


On July 1, 1988, the fourth and last day of a bruising 19th Party Conference, Gorbachev won the backing of the tired delegates for his last-minute proposal to create a new supreme legislative body called the Congress of People's Deputies. Frustrated by the old guard's resistance, Gorbachev embarked on a set of constitutional changes to try to separate party and state, and thereby isolate his conservative Party opponents. Detailed proposals for the new Congress of People's Deputies were published on October 2, 1988, and to enable the creation of the new legislature the Supreme Soviet, during its November 29–December 1, 1988, session, implemented amendments to the 1977 Soviet Constitution, enacted a law on electoral reform, and set the date of the election for March 26, 1989.


On October 2, the Popular Front formally launched its political platform at a two-day congress. Väljas attended, gambling that the front could help Estonia become a model of economic and political revival, while moderating separatist and other radical tendencies. On November 16, 1988, the Supreme Soviet of the Estonian SSR adopted a declaration of national sovereignty under which Estonian laws would take precedence over those of the Soviet Union. Estonia's parliament also laid claim to the republic's natural resources including land, inland waters, forests, mineral deposits, and to the means of industrial production, agriculture, construction, state banks, transportation, and municipal services within the territory of Estonia's borders.


In February 20, 1988, after a week of growing demonstrations in Stepanakert, capital of the Nagorno-Karabakh Autonomous Oblast (the Armenian majority area within Azerbaijan Soviet Socialist Republic), the Regional Soviet voted to secede and join with the Soviet Socialist Republic of Armenia. This local vote in a small, remote part of the Soviet Union made headlines around the world; it was an unprecedented defiance of republic and national authorities. On February 22, 1988, in what became known as the "Askeran clash", two Azerbaijanis were killed by Karabakh police. These deaths, announced on state radio, led to the Sumgait Pogrom. Between February 26 and March 1, the city of Sumgait (Azerbaijan) saw violent anti-Armenian rioting during which 32 people were killed. The authorities totally lost control and occupied the city with paratroopers and tanks; nearly all of the 14,000 Armenian residents of Sumgait fled.


Gorbachev refused to make any changes to the status of Nagorno Karabakh, which remained part of Azerbaijan. He instead sacked the Communist Party Leaders in both Republics – on May 21, 1988, Kamran Baghirov was replaced by Abdulrahman Vezirov as First Secretary of the Azerbaijan Communist Party. From July 23 to September 1988, a group of Azerbaijani intellectuals began working for a new organization called the Popular Front of Azerbaijan, loosely based on the Estonian Popular Front. On September 17, when gun battles broke out between the Armenians and Azerbaijanis near Stepanakert, two soldiers were killed and more than two dozen injured. This led to almost tit-for-tat ethnic polarization in Nagorno-Karabakh's two main towns: The Azerbaijani minority was expelled from Stepanakert, and the Armenian minority was expelled from Shusha. On November 17, 1988, in response to the exodus of tens of thousands of Azerbaijanis from Armenia, a series of mass demonstrations began in Baku's Lenin Square, lasting 18 days and attracting half a million demonstrators. On December 5, 1988, the Soviet militia finally moved in, cleared the square by force, and imposed a curfew that lasted ten months.


The rebellion of fellow Armenians in Nagorno-Karabakh had an immediate effect in Armenia itself. Daily demonstrations, which began in the Armenian capital Yerevan on February 18, initially attracted few people, but each day the Nagorno-Karabakh issue became increasingly prominent and numbers swelled. On February 20, a 30,000-strong crowd demonstrated in Theater Square, by February 22, there were 100,000, the next day 300,000, and a transport strike was declared, by February 25, there were close to 1 million demonstrators – about a quarter of Armenia's population. This was the first of the large, peaceful public demonstrations that would become a feature of communism's overthrow in Prague, Berlin, and, ultimately, Moscow. Leading Armenian intellectuals and nationalists, including future first President of independent Armenia Levon Ter-Petrossian, formed the eleven-member Karabakh Committee to lead and organize the new movement.


Gorbachev again refused to make any changes to the status of Nagorno Karabakh, which remained part of Azerbaijan. Instead he sacked both Republics' Communist Party Leaders: On May 21, 1988, Karen Demirchian was replaced by Suren Harutyunyan as First Secretary of the Communist Party of Armenia. However, Harutyunyan quickly decided to run before the nationalist wind and on May 28, allowed Armenians to unfurl the red-blue-gold First Armenian Republic flag for the first time in almost 70 years. On June 15, 1988, the Armenian Supreme Soviet adopted a resolution formally approving the idea of Nagorno Karabakh joining Armenia. Armenia, formerly one of the most loyal Republics, had suddenly turned into the leading rebel republic. On July 5, 1988, when a contingent of troops was sent in to remove demonstrators by force from Yerevan's Zvartnots International Airport, shots were fired and one student protester was killed. In September, further large demonstrations in Yerevan led to the deployment of armored vehicles. In the autumn of 1988 almost all the 200,000 Azerbaijani minority in Armenia was expelled by Armenian Nationalists, with over 100 killed in the process – this, after the Sumgait pogrom earlier that year carried out by Azerbaijanis against ethnic Armenians and subsequent expulsion of all Armenians from Azerbaijan. On November 25, 1988, a military commandant took control of Yerevan as the Soviet government moved to prevent further ethnic violence.


Beginning in February 1988, the Democratic Movement of Moldova (formerly Moldavia) organized public meetings, demonstrations, and song festivals, which gradually grew in size and intensity. In the streets, the center of public manifestations was the Stephen the Great Monument in Chişinău, and the adjacent park harboring Aleea Clasicilor (The "Alee of the Classics [of the Literature]"). On January 15, 1988, in a tribute to Mihai Eminescu at his bust on the Aleea Clasicilor, Anatol Şalaru submitted a proposal to continue the meetings. In the public discourse, the movement called for national awakening, freedom of speech, revival of Moldavian traditions, and for attainment of official status for the Romanian language and return to the Latin alphabet. The transition from "movement" (an informal association) to "front" (a formal association) was seen as a natural "upgrade" once a movement gained momentum with the public, and the Soviet authorities no longer dared to crack down on it.


On April 26, 1988, about 500 people participated in a march organized by the Ukrainian Cultural Club on Kiev's Khreschatyk Street to mark the second anniversary of the Chernobyl nuclear disaster, carrying placards with slogans like "Openness and Democracy to the End." Between May and June 1988, Ukrainian Catholics in western Ukraine celebrated the Millennium of Christianity in Kievan Rus' in secret by holding services in the forests of Buniv, Kalush, Hoshiv, and Zarvanytsia. On June 5, 1988, as the official celebrations of the Millennium were held in Moscow, the Ukrainian Cultural Club hosted its own observances in Kiev at the monument to St. Volodymyr the Great, the grand prince of Kievan Rus'.


On June 16, 1988, 6,000 to 8,000 people gathered in Lviv to hear speakers declare no confidence in the local list of delegates to the 19th Communist Party conference, to begin on June 29. On June 21, a rally in Lviv attracted 50,000 people who had heard about a revised delegate list. Authorities attempted to disperse the rally in front of Druzhba Stadium. On July 7, 10,000 to 20,000 people witnessed the launch of the Democratic Front to Promote Perestroika. On July 17, a group of 10,000 gathered in the village Zarvanytsia for Millennium services celebrated by Ukrainian Greek-Catholic Bishop Pavlo Vasylyk. The militia tried to disperse attendees, but it turned out to be the largest gathering of Ukrainian Catholics since Stalin outlawed the Church in 1946. On August 4, which came to be known as "Bloody Thursday," local authorities violently suppressed a demonstration organized by the Democratic Front to Promote Perestroika. Forty-one people were detained, fined, or sentenced to 15 days of administrative arrest. On September 1, local authorities violently displaced 5,000 students at a public meeting lacking official permission at Ivan Franko State University.


On November 13, 1988, approximately 10,000 people attended an officially sanctioned meeting organized by the cultural heritage organization Spadschyna, the Kyiv University student club Hromada, and the environmental groups Zelenyi Svit ("Green World") and Noosfera, to focus on ecological issues. From November 14–18, 15 Ukrainian activists were among the 100 human-, national- and religious-rights advocates invited to discuss human rights with Soviet officials and a visiting delegation of the U.S. Commission on Security and Cooperation in Europe (also known as the Helsinki Commission). On December 10, hundreds gathered in Kiev to observe International Human Rights Day at a rally organized by the Democratic Union. The unauthorized gathering resulted in the detention of local activists.


The Partyja BPF (Belarusian Popular Front) was established in 1988 as a political party and cultural movement for democracy and independence, à la the Baltic republics’ popular fronts. The discovery of mass graves in Kurapaty outside Minsk by historian Zianon Pazniak, the Belarusian Popular Front’s first leader, gave additional momentum to the pro-democracy and pro-independence movement in Belarus. It claimed that the NKVD performed secret killings in Kurapaty. Initially the Front had significant visibility because its numerous public actions almost always ended in clashes with the police and the KGB.


Spring 1989 saw the people of the Soviet Union exercising a democratic choice, albeit limited, for the first time since 1917, when they elected the new Congress of People's Deputies. Just as important was the uncensored live TV coverage of the legislature's deliberations, where people witnessed the previously feared Communist leadership being questioned and held accountable. This example fueled a limited experiment with democracy in Poland, which quickly led to the toppling of the Communist government in Warsaw that summer – which in turn sparked uprisings that overthrew communism in the other five Warsaw Pact countries before the end of 1989, the year the Berlin Wall fell. These events showed that the people of Eastern Europe and the Soviet Union did not support Gorbachev's drive to modernize Communism; rather, they preferred to abandon it altogether.


In the March 26 general elections, voter participation was an impressive 89.8%, and 1,958 (including 1,225 district seats) of the 2,250 CPD seats were filled. In district races, run-off elections were held in 76 constituencies on April 2 and 9 and fresh elections were organized on April 20 and 14 to May 23, in the 199 remaining constituencies where the required absolute majority was not attained. While most CPSU-endorsed candidates were elected, more than 300 lost to independent candidates such as Yeltsin, physicist Andrei Sakharov and lawyer Anatoly Sobchak.


In the first session of the new Congress of People's Deputies, from May 25 to June 9, hardliners retained control but reformers used the legislature as a platform for debate and criticism – which was broadcast live and uncensored. This transfixed the population; nothing like this freewheeling debate had ever been witnessed in the U.S.S.R. On May 29, Yeltsin managed to secure a seat on the Supreme Soviet, and in the summer he formed the first opposition, the Inter-Regional Deputies Group, composed of Russian nationalists and liberals. Composing the final legislative group in the Soviet Union, those elected in 1989 played a vital part in reforms and the eventual breakup of the Soviet Union during the next two years.


On October 25, 1989, the Supreme Soviet voted to eliminate special seats for the Communist Party and other official organizations in national and local elections, responding to sharp popular criticism that such reserved slots were undemocratic. After vigorous debate, the 542-member Supreme Soviet passed the measure 254-85 (with 36 abstentions). The decision required a constitutional amendment, ratified by the full congress, which met December 12–25. It also passed measures that would allow direct elections for presidents of each of the 15 constituent republics. Gorbachev strongly opposed such a move during debate but was defeated.


The six Warsaw Pact countries of Eastern Europe, while nominally independent, were widely recognized in the international community as the Soviet satellite states. All had been occupied by the Soviet Red Army in 1945, had Soviet-style socialist states imposed upon them, and had very restricted freedom of action in either domestic or international affairs. Any moves towards real independence were suppressed by military force – in the Hungarian Revolution of 1956 and the Prague Spring in 1968. Gorbachev abandoned the oppressive and expensive Brezhnev Doctrine, which mandated intervention in the Warsaw Pact states, in favor of non-intervention in the internal affairs of allies – jokingly termed the Sinatra Doctrine in a reference to the Frank Sinatra song "My Way".


The Baltic Way or Baltic Chain (also Chain of Freedom Estonian: Balti kett, Latvian: Baltijas ceļš, Lithuanian: Baltijos kelias, Russian: Балтийский путь) was a peaceful political demonstration on August 23, 1989. An estimated 2 million people joined hands to form a human chain extending 600 kilometres (370 mi) across Estonia, Latvia and Lithuania, which had been forcibly reincorporated into the Soviet Union in 1944. The colossal demonstration marked the 50th anniversary of the Molotov–Ribbentrop Pact that divided Eastern Europe into spheres of influence and led to the occupation of the Baltic states in 1940.


On December 7, 1989, the Communist Party of Lithuania under the leadership of Algirdas Brazauskas, split from the Communist Party of the Soviet Union and abandoned its claim to have a constitutional "leading role" in politics. A smaller loyalist faction of the Communist Party, headed by hardliner Mykolas Burokevičius, was established and remained affiliated with the CPSU. However, Lithuania’s governing Communist Party was formally independent from Moscow's control – a first for Soviet Republics and a political earthquake that prompted Gorbachev to arrange a visit to Lithuania the following month in a futile attempt to bring the local party back under control.


On July 16, 1989, the Popular Front of Azerbaijan held its first congress and elected Abulfaz Elchibey, who would become President, as its Chairman. On August 19, 600,000 protesters jammed Baku’s Lenin Square (now Azadliq Square) to demand the release of political prisoners. In the second half of 1989, weapons were handed out in Nagorno-Karabakh. When Karabakhis got hold of small arms to replace hunting rifles and crossbows, casualties began to mount; bridges were blown up, roads were blockaded, and hostages were taken.


In a new and effective tactic, the Popular Front launched a rail blockade of Armenia, which caused petrol and food shortages because 85 percent of Armenia's freight came from Azerbaijan. Under pressure from the Popular Front the Communist authorities in Azerbaijan started making concessions. On September 25, they passed a sovereignty law that gave precedence to Azerbaijani law, and on October 4, the Popular Front was permitted to register as a legal organization as long as it lifted the blockade. Transport communications between Azerbaijan and Armenia never fully recovered. Tensions continued to escalate and on December 29, Popular Front activists seized local party offices in Jalilabad, wounding dozens.


On April 7, 1989, Soviet troops and armored personnel carriers were sent to Tbilisi after more than 100,000 people protested in front of Communist Party headquarters with banners calling for Georgia to secede from the Soviet Union and for Abkhazia to be fully integrated into Georgia. On April 9, 1989, troops attacked the demonstrators; some 20 people were killed and more than 200 wounded. This event radicalized Georgian politics, prompting many to conclude that independence was preferable to continued Soviet rule. On April 14, Gorbachev removed Jumber Patiashvili as First Secretary of the Georgian Communist Party and replaced him with former Georgian KGB chief Givi Gumbaridze.


In Ukraine, Lviv and Kiev celebrated Ukrainian Independence Day on January 22, 1989. Thousands gathered in Lviv for an unauthorized moleben (religious service) in front of St. George's Cathedral. In Kiev, 60 activists met in a Kiev apartment to commemorate the proclamation of the Ukrainian People's Republic in 1918. On February 11–12, 1989, the Ukrainian Language Society held its founding congress. On February 15, 1989, the formation of the Initiative Committee for the Renewal of the Ukrainian Autocephalous Orthodox Church was announced. The program and statutes of the movement were proposed by the Writers Association of Ukraine and were published in the journal Literaturna Ukraina on February 16, 1989. The organization heralded Ukrainian dissidents such as Vyacheslav Chornovil.


In late February, large public rallies took place in Kiev to protest the election laws, on the eve of the March 26 elections to the USSR Congress of People's Deputies, and to call for the resignation of the first secretary of the Communist Party of Ukraine, Volodymyr Scherbytsky, lampooned as "the mastodon of stagnation." The demonstrations coincided with a visit to Ukraine by Soviet President Gorbachev. On February 26, 1989, between 20,000 and 30,000 people participated in an unsanctioned ecumenical memorial service in Lviv, marking the anniversary of the death of 19th Century Ukrainian artist and nationalist Taras Shevchenko.


On March 4, 1989, the Memorial Society, committed to honoring the victims of Stalinism and cleansing society of Soviet practices, was founded in Kiev. A public rally was held the next day. On March 12, A pre-election meeting organized in Lviv by the Ukrainian Helsinki Union and the Marian Society Myloserdia (Compassion) was violently dispersed, and nearly 300 people were detained. On March 26, elections were held to the union Congress of People's Deputies; by-elections were held on April 9, May 14, and May 21. Among the 225 Ukrainian deputies, most were conservatives, though a handful of progressives made the cut.


From April 20–23, 1989, pre-election meetings were held in Lviv for four consecutive days, drawing crowds of up to 25,000. The action included an one-hour warning strike at eight local factories and institutions. It was the first labor strike in Lviv since 1944. On May 3, a pre-election rally attracted 30,000 in Lviv. On May 7, The Memorial Society organized a mass meeting at Bykivnia, site of a mass grave of Ukrainian and Polish victims of Stalinist terror. After a march from Kiev to the site, a memorial service was staged.


From mid-May to September 1989, Ukrainian Greek-Catholic hunger strikers staged protests on Moscow's Arbat to call attention to the plight of their Church. They were especially active during the July session of the World Council of Churches held in Moscow. The protest ended with the arrests of the group on September 18. On May 27, 1989, the founding conference of the Lviv regional Memorial Society was held. On June 18, 1989, an estimated 100,000 faithful participated in public religious services in Ivano-Frankivsk in western Ukraine, responding to Cardinal Myroslav Lubachivsky's call for an international day of prayer.


On August 19, 1989, the Russian Orthodox Parish of Saints Peter and Paul announced it would be switching to the Ukrainian Autocephalous Orthodox Church. On September 2, 1989, tens of thousands across Ukraine protested a draft election law that reserved special seats for the Communist Party and for other official organizations: 50,000 in Lviv, 40,000 in Kiev, 10,000 in Zhytomyr, 5,000 each in Dniprodzerzhynsk and Chervonohrad, and 2,000 in Kharkiv. From September 8–10, 1989, writer Ivan Drach was elected to head Rukh, the People's Movement of Ukraine, at its founding congress in Kiev. On September 17, between 150,000 and 200,000 people marched in Lviv, demanding the legalization of the Ukrainian Greek Catholic Church. On September 21, 1989, exhumation of a mass grave begins in Demianiv Laz, a nature preserve south of Ivano-Frankivsk. On September 28, First Secretary of the Communist Party of the Ukraine Volodymyr Shcherbytsky, a holdover from the Brezhnev era, was replaced by Vladimir Ivashko.


On October 1, 1989, a peaceful demonstration of 10,000 to 15,000 people was violently dispersed by the militia in front of Lviv's Druzhba Stadium, where a concert celebrating the Soviet "reunification" of Ukrainian lands was being held. On October 10, Ivano-Frankivsk was the site of a pre-election protest attended by 30,000 people. On October 15, several thousand people gathered in Chervonohrad, Chernivtsi, Rivne, and Zhytomyr; 500 in Dnipropetrovsk; and 30,000 in Lviv to protest the election law. On October 20, faithful and clergy of the Ukrainian Autocephalous Orthodox Church participated in a synod in Lviv, the first since its forced liquidation in the 1930s.


On October 24, the union Supreme Soviet passed a law eliminating special seats for Communist Party and other official organizations' representatives. On October 26, twenty factories in Lviv held strikes and meetings to protest the police brutality of October 1 and the authorities' unwillingness to prosecute those responsible. From October 26–28, the Zelenyi Svit (Friends of the Earth – Ukraine) environmental association held its founding congress, and on October 27 the Ukrainian Supreme Soviet passed a law eliminating the special status of party and other official organizations.


On October 28, 1989, the Ukrainian Supreme Soviet decreed that effective January 1, 1990, Ukrainian would be the official language of Ukraine, while Russian would be used for communication between ethnic groups. On the same day The Congregation of the Church of the Transfiguration in Lviv left the Russian Orthodox Church and proclaimed itself the Ukrainian Greek Catholic Church. The following day, thousands attended a memorial service at Demianiv Laz, and a temporary marker was placed to indicate that a monument to the "victims of the repressions of 1939–1941" soon would be erected.


In mid-November The Shevchenko Ukrainian Language Society was officially registered. On November 19, 1989, a public gathering in Kiev attracted thousands of mourners, friends and family to the reburial in Ukraine of three inmates of the infamous Gulag Camp No. 36 in Perm in the Ural Mountains: human-rights activists Vasyl Stus, Oleksiy Tykhy, and Yuriy Lytvyn. Their remains were reinterred in Baikove Cemetery. On November 26, 1989, a day of prayer and fasting was proclaimed by Cardinal Myroslav Lubachivsky, thousands of faithful in western Ukraine participated in religious services on the eve of a meeting between Pope John Paul II and Soviet President Gorbachev. On November 28, 1989, the Ukrainian SSR's Council for Religious Affairs issued a decree allowing Ukrainian Catholic congregations to register as legal organizations. The decree was proclaimed on December 1, coinciding with a meeting at the Vatican between the pope and the Soviet president.


On September 30, 1989, thousands of Belorussians, denouncing local leaders, marched through Minsk to demand additional cleanup of the 1986 Chernobyl disaster site in Ukraine. Up to 15,000 protesters wearing armbands bearing radioactivity symbols and carrying the banned red-and-white Belorussian national flag filed through torrential rain in defiance of a ban by local authorities. Later, they gathered in the city center near the government's headquarters, where speakers demanded resignation of Yefrem Sokolov, the republic's Communist Party leader, and called for the evacuation of half a million people from the contaminated zones.


Thousands of Soviet troops were sent to the Fergana Valley, southeast of the Uzbek capital Tashkent, to re-establish order after clashes in which local Uzbeks hunted down members of the Meskhetian minority in several days of rioting between June 4–11, 1989; about 100 people were killed. On June 23, 1989, Gorbachev removed Rafiq Nishonov as First Secretary of the Communist Party of the Uzbek SSR and replaced him with Karimov, who went on to lead Uzbekistan as a Soviet Republic and subsequently as an independent state.


In Kazakhstan on June 19, 1989, young men carrying guns, firebombs, iron bars and stones rioted in Zhanaozen, causing a number of deaths. The youths tried to seize a police station and a water-supply station. They brought public transportation to a halt and shut down various shops and industries. By June 25, the rioting had spread to five other towns near the Caspian Sea. A mob of about 150 people armed with sticks, stones and metal rods attacked the police station in Mangishlak, about 90 miles from Zhanaozen, before they were dispersed by government troops flown in by helicopters. Mobs of young people also rampaged through Yeraliev, Shepke, Fort-Shevchenko and Kulsary, where they poured flammable liquid on trains housing temporary workers and set them on fire.


Ethnic tensions had escalated between the Armenians and Azerbaijanis in spring and summer 1988. On January 9, 1990, after the Armenian parliament voted to include Nagorno-Karabakh within its budget, renewed fighting broke out, hostages were taken, and four Soviet soldiers were killed. On January 11, Popular Front radicals stormed party buildings and effectively overthrew the communist powers in the southern town of Lenkoran. Gorbachev resolved to regain control of Azerbaijan; the events that ensued are known as "Black January." Late on January 19, 1990, after blowing up the central television station and cutting the phone and radio lines, 26,000 Soviet troops entered the Azerbaijani capital Baku, smashing barricades, attacking protesters, and firing into crowds. On that night and during subsequent confrontations (which lasted until February), more than 130 people died – the majority of whom were civilians. More than 700 civilians were wounded, hundreds were detained, but only a few were actually tried for alleged criminal offenses.


Following the hardliners' takeover, the September 30, 1990 elections (runoffs on October 14) were characterized by intimidation; several Popular Front candidates were jailed, two were murdered, and unabashed ballot stuffing took place even in the presence of Western observers. The election results reflected the threatening environment; out of the 350 members, 280 were Communists, with only 45 opposition candidates from the Popular Front and other non-communist groups, who together formed a Democratic Bloc ("Dembloc"). In May 1990 Mutalibov was elected Chairman of the Supreme Soviet unopposed.


On January 21, 1990, Rukh organized a 300-mile (480 km) human chain between Kiev, Lviv, and Ivano-Frankivsk. Hundreds of thousands joined hands to commemorate the proclamation of Ukrainian independence in 1918 and the reunification of Ukrainian lands one year later (1919 Unification Act). On January 23, 1990, the Ukrainian Greek-Catholic Church held its first synod since its liquidation by the Soviets in 1946 (an act which the gathering declared invalid). On February 9, 1990, the Ukrainian Ministry of Justice officially registered Rukh. However, the registration came too late for Rukh to stand its own candidates for the parliamentary and local elections on March 4. At the 1990 elections of people's deputies to the Supreme Council (Verkhovna Rada), candidates from the Democratic Bloc won landslide victories in western Ukrainian oblasts. A majority of the seats had to hold run-off elections. On March 18, Democratic candidates scored further victories in the run-offs. The Democratic Bloc gained about 90 out of 450 seats in the new parliament.


On April 6, 1990, the Lviv City Council voted to return St. George Cathedral to the Ukrainian Greek Catholic Church. The Russian Orthodox Church refused to yield. On April 29–30, 1990, the Ukrainian Helsinki Union disbanded to form the Ukrainian Republican Party. On May 15 the new parliament convened. The bloc of conservative communists held 239 seats; the Democratic Bloc, which had evolved into the National Council, had 125 deputies. On June 4, 1990, two candidates remained in the protracted race for parliament chair. The leader of the Communist Party of Ukraine (CPU), Volodymyr Ivashko, was elected with 60 percent of the vote as more than 100 opposition deputies boycotted the election. On June 5–6, 1990, Metropolitan Mstyslav of the U.S.-based Ukrainian Orthodox Church was elected patriarch of the Ukrainian Autocephalous Orthodox Church (UAOC) during that Church's first synod. The UAOC declared its full independence from the Moscow Patriarchate of the Russian Orthodox Church, which in March had granted autonomy to the Ukrainian Orthodox church headed by Metropolitan Filaret.


On June 22, 1990, Volodymyr Ivashko withdrew his candidacy for leader of the Communist Party of Ukraine in view of his new position in parliament. Stanislav Hurenko was elected first secretary of the CPU. On July 11, Ivashko resigned from his post as chairman of the Ukrainian Parliament after he was elected deputy general secretary of the Communist Party of the Soviet Union. The Parliament accepted the resignation a week later, on July 18. On July 16 Parliament overwhelmingly approved the Declaration on State Sovereignty of Ukraine - with a vote of 355 in favour and four against. The people's deputies voted 339 to 5 to proclaim July 16 a Ukrainian national holiday.


On July 23, 1990, Leonid Kravchuk was elected to replace Ivashko as parliament chairman. On July 30, Parliament adopted a resolution on military service ordering Ukrainian soldiers "in regions of national conflict such as Armenia and Azerbaijan" to return to Ukrainian territory. On August 1, Parliament voted overwhelmingly to shut down the Chernobyl Nuclear Power Plant. On August 3, it adopted a law on the economic sovereignty of the Ukrainian republic. On August 19, the first Ukrainian Catholic liturgy in 44 years was celebrated at St. George Cathedral. On September 5–7, the International Symposium on the Great Famine of 1932–1933 was held in Kiev. On September 8, The first "Youth for Christ" rally since 1933 took place held in Lviv, with 40,000 participants. In September 28–30, the Green Party of Ukraine held its founding congress. On September 30, nearly 100,000 people marched in Kiev to protest against the new union treaty proposed by Gorbachev.