LaserDisc did not have high market penetration in North America due to the high cost of the players and discs, which were far more expensive than VHS players and tapes, and due to marketplace confusion with the technologically inferior CED, which also went by the name Videodisc. While the format was not widely adopted by North American consumers, it was well received among videophiles due to the superior audio and video quality compared to VHS and Betamax tapes, finding a place in nearly one million American homes by the end of 1990. The format was more popular in Japan than in North America because prices were kept low to ensure adoption, resulting in minimal price differences between VHS tapes and the higher quality LaserDiscs, helping ensure that it quickly became the dominant consumer video format in Japan. Anime collectors in every country the LD format was released, which includes both North America and Japan, also quickly became familiar with this format, and sought the higher video and sound quality of LaserDisc and the availability of numerous titles not available on VHS. LaserDiscs were also popular alternatives to videocassettes among movie enthusiasts in the more affluent regions of South East Asia, such as Singapore, due to their high integration with the Japanese export market and the disc-based media's superior longevity compared to videocassette, especially in the humid conditions endemic to that area of the world.


The format also became quite popular in Hong Kong during the 1990s before the introduction of VCDs and DVD; although people rarely bought the discs (because each LD was priced around USD100), high rental activity helped the video rental business in the city grow larger than it had ever been previously. Due to integration with the Japanese export market, NTSC LaserDiscs were used in the Hong Kong market, in contrast to the PAL standard used for broadcast (This anomaly also exists for DVD). This created a market for multi-system TVs and multi-system VCRs which could display or play both PAL and NTSC materials in addition to SECAM materials (which were never popular in Hong Kong). Some LD players could convert NTSC signals to PAL so that most TVs used in Hong Kong could display the LD materials.


Although the LaserDisc format was supplanted by DVD by the late 1990s, many LD titles are still highly coveted by movie enthusiasts (for example, Disney's Song of the South which is unavailable in the US in any format, but was issued in Japan on LD). This is largely because there are many films that are still only available on LD and many other LD releases contain supplemental material not available on subsequent DVD versions of those films. Until the end of 2001, many titles were released on VHS, LD, and DVD in Japan.


In the early 1980s, Philips produced a LaserDisc player model adapted for a computer interface, dubbed "professional". In 1985, Jasmine Multimedia created LaserDisc Juke Boxes featuring music videos from Michael Jackson, Duran Duran, and Cyndi Lauper. When connected to a PC this combination could be used to display images or information for educational or archival purposes, for example thousands of scanned medieval manuscripts. This strange device could be considered a very early equivalent of a CD-ROM.


In the mid-1980s Lucasfilm pioneered the EditDroid non-linear editing system for film and television based on computer-controlled LaserDisc players. Instead of printing dailies out on film, processed negatives from the day's shoot would be sent to a mastering plant to be assembled from their 10-minute camera elements into 20-minute film segments. These were then mastered onto single-sided blank LaserDiscs, just as a DVD would be burnt at home today, allowing for much easier selection and preparation of an Edit Decision List. In the days before video assist was available in cinematography, this was the only other way a film crew could see their work. The EDL went to the negative cutter who then cut the camera negative accordingly and assembled the finished film. Only 24 EditDroid systems were ever built, even though the ideas and technology are still in use today. Later EditDroid experiments borrowed from hard-drive technology of having multiple discs on the same spindle and added numerous playback heads and numerous electronics to the basic jukebox design so that any point on each of the discs would be accessible within seconds. This eliminated the need for racks and racks of industrial LaserDisc players since EditDroid discs were only single-sided.


In 1986, a SCSI-equipped LaserDisc player attached to a BBC Master computer was used for the BBC Domesday Project. The player was referred as an LV-ROM (LaserVision Read Only Memory) as the discs contained the driving software as well as the video frames. The discs used the CAV format, and encoded data as a binary signal represented by the analog audio recording. These discs could contain in each CAV frame video/audio or video/binary data, but not both. "Data" frames would appear blank when played as video. It was typical for each disc to start with the disc catalog (a few blank frames) then the video introduction before the rest of the data. Because the format (based on the ADFS hard disc format) used a starting sector for each file, the data layout effectively skipped over any video frames. If all 54,000 frames are used for data storage an LV-ROM disc can contain 324 MB of data per side. The Domesday Project systems also included a genlock, allowing video frames, clips and audio to be mixed with graphics originated from the BBC Master; this was used to great effect for displaying high resolution photographs and maps, which could then be zoomed into.


Apple's HyperCard scripting language provided Macintosh computer users with a means to design databases of slides, animation, video and sounds from LaserDiscs and then to create interfaces for users to play specific content from the disc through software called LaserStacks. User-created "stacks" were shared and were especially popular in education where teacher-generated stacks were used to access discs ranging from art collections to basic biological processes. Commercially available stacks were also popular with the Voyager company being possibly the most successful distributor.


Under contract from the U.S. Military, Matrox produced a combination computer/LaserDisc player for instructional purposes. The computer was a 286, the LaserDisc player only capable of reading the analog audio tracks. Together they weighed 43 lb (20 kg) and sturdy handles were provided in case two people were required to lift the unit. The computer controlled the player via a 25-pin serial port at the back of the player and a ribbon cable connected to a proprietary port on the motherboard. Many of these were sold as surplus by the military during the 1990s, often without the controller software. Nevertheless, it is possible to control the unit by removing the ribbon cable and connecting a serial cable directly from the computer's serial port to the port on the LaserDisc player.


The format's instant-access capability made it possible for a new breed of LaserDisc-based video arcade games and several companies saw potential in using LaserDiscs for video games in the 1980s and 1990s, beginning in 1983 with Sega's Astron Belt. American Laser Games and Cinematronics produced elaborate arcade consoles that used the random-access features to create interactive movies such as Dragon's Lair and Space Ace. Similarly, the Pioneer Laseractive and Halcyon were introduced as home video game consoles that used LaserDisc media for their software.


In 1991, several manufacturers announced specifications for what would become known as MUSE LaserDisc, representing a span of almost 15 years until the feats of this HD analog optical disc system would finally be duplicated digitally by HD DVD and Blu-ray Disc. Encoded using NHK's MUSE "Hi-Vision" analogue TV system, MUSE discs would operate like standard LaserDiscs but would contain high-definition 1,125-line (1,035 visible lines) (Sony HDVS) video with a 5:3 aspect ratio. The MUSE players were also capable of playing standard NTSC format discs and are superior in performance to non-MUSE players even with these NTSC discs. The MUSE-capable players had several noteworthy advantages over standard LaserDisc players, including a red laser with a much narrower wavelength than the lasers found in standard players. The red laser was capable of reading through disc defects such as scratches and even mild disc rot that would cause most other players to stop, stutter or drop-out. Crosstalk was not an issue with MUSE discs, and the narrow wavelength of the laser allowed for the virtual elimination of crosstalk with normal discs.


In order to view MUSE encoded discs, it was necessary to have a MUSE decoder in addition to a compatible player. There are televisions with MUSE decoding built-in and set top tuners with decoders that can provide the proper MUSE input. Equipment prices were high, especially for early HDTVs which generally eclipsed US$10,000, and even in Japan the market for MUSE was tiny. Players and discs were never officially sold in North America, although several distributors imported MUSE discs along with other import titles. Terminator 2: Judgment Day, Lawrence of Arabia, A League of Their Own, Bugsy, Close Encounters of the Third Kind, Bram Stoker's Dracula and Chaplin were among the theatrical releases available on MUSE LDs. Several documentaries, including one about Formula One at Japan's Suzuka Circuit were also released.


With the release of 16:9 televisions in the mid-1990s, Pioneer and Toshiba decided that it was time to take advantage of this aspect ratio. Squeeze LDs were enhanced 16:9-ratio widescreen LaserDiscs. During the video transfer stage, the movie was stored in an anamorphic "squeezed" format. The widescreen movie image was stretched to fill the entire video frame with less or none of the video resolution wasted to create letterbox bars. The advantage was a 33% greater vertical resolution compared to letterboxed widescreen LaserDisc. This same procedure was used for anamorphic DVDs, but unlike all DVD players, very few LD players had the ability to unsqueeze the image for 4:3 sets, and very few if any 4:3 sets could be set to play them properly either. If the discs were played on a standard 4:3 television the image would be distorted. Since very few people owned 16:9 displays, the marketability of these special discs was very limited.


There were no anamorphic LaserDisc titles available in the US except for promotional purposes. Upon purchase of a Toshiba 16:9 television viewers had the option of selecting a number of Warner Bros. 16:9 films. Titles include Unforgiven, Grumpy Old Men, The Fugitive, and Free Willy. The Japanese lineup of titles was different. A series of releases under the banner "SQUEEZE LD" from Pioneer of mostly Carolco titles included Basic Instinct, Stargate, Terminator 2: Judgment Day, Showgirls, Cutthroat Island, and Cliffhanger. Terminator 2 was released twice in Squeeze LD, the second release being THX certified and a notable improvement over the first.


Another form of recordable LaserDisc that is completely playback-compatible with the LaserDisc format (unlike CRVdisc with its caddy enclosure) is the RLV, or Recordable LaserVision disc. It was developed and first marketed by the Optical Disc Corporation (ODC, now ODC Nimbus) in 1984. RLV discs, like CRVdisc, are also a WORM technology, and function exactly like a CD-R disc. RLV discs look almost exactly like standard LaserDiscs, and can play in any standard LaserDisc player after they have been recorded.


The only cosmetic difference between an RLV disc and a regular factory-pressed LaserDiscs is their reflective purple-violet (or blue with some RLV discs) color resulting from the dye embedded in the reflective layer of the disc to make it recordable, as opposed to the silver mirror appearance of regular LDs. The purplish color of RLVs is very similar to DVD-R and DVD+R discs. RLVs were popular for making short-run quantities of LaserDiscs for specialized applications such as interactive kiosks and flight simulators.


There were also 12 cm (4.7 in) (CD size) "single"-style discs produced that were playable on LaserDisc players. These were referred to as CD Video (CD-V) discs, and Video Single Discs (VSD). A CD-V carried up to five minutes of analog LaserDisc-type video content (usually a music video), as well as up to 20 minutes of digital audio CD tracks. The original 1989 release of David Bowie's retrospective Sound + Vision CD box set prominently featured a CD-V video of Ashes to Ashes, and standalone promo CD-Vs featured the video, plus three audio tracks: "John, I'm Only Dancing", "Changes", and "The Supermen".


CD-Vs are not to be confused with Video CDs (which are all-digital and can only be played on VCD players, DVD players, CD-i players, computers, and later-model LaserDisc players, such as the DVL series from Pioneer that can also play DVDs). CD-Vs can only be played back on LaserDisc players with CD-V capability. VSDs were the same as CD-Vs, but without the audio CD tracks. CD-Vs were somewhat popular for a brief time worldwide, but soon faded from view. VSDs were popular only in Japan and other parts of Asia, and were never fully introduced to the rest of the world.


During George's reign the break-up of the British Empire and its transition into the Commonwealth of Nations accelerated. The parliament of the Irish Free State removed direct mention of the monarch from the country's constitution on the day of his accession. From 1939, the Empire and Commonwealth, except Ireland, was at war with Nazi Germany. War with Italy and Japan followed in 1940 and 1941, respectively. Though Britain and its allies were ultimately victorious in 1945, the United States and the Soviet Union rose as pre-eminent world powers and the British Empire declined. After the independence of India and Pakistan in 1947, George remained as king of both countries, but the title Emperor of India was abandoned in June 1948. Ireland formally declared itself a republic and left the Commonwealth in 1949, and India became a republic within the Commonwealth the following year. George adopted the new title of Head of the Commonwealth. He was beset by health problems in the later years of his reign. His elder daughter, Elizabeth, succeeded him.


His birthday (14 December 1895) was the 34th anniversary of the death of his great-grandfather, Prince Albert, the Prince Consort. Uncertain of how the Prince Consort's widow, Queen Victoria, would take the news of the birth, the Prince of Wales wrote to the Duke of York that the Queen had been "rather distressed". Two days later, he wrote again: "I really think it would gratify her if you yourself proposed the name Albert to her". Queen Victoria was mollified by the proposal to name the new baby Albert, and wrote to the Duchess of York: "I am all impatience to see the new one, born on such a sad day but rather more dear to me, especially as he will be called by that dear name which is a byword for all that is great and good". Consequently, he was baptised "Albert Frederick Arthur George" at St. Mary Magdalene's Church near Sandringham three months later.[a] As a great-grandson of Queen Victoria, he was known formally as His Highness Prince Albert of York from birth. Within the family, he was known informally as "Bertie". His maternal grandmother, the Duchess of Teck, did not like the first name the baby had been given, and she wrote prophetically that she hoped the last name "may supplant the less favoured one".


Albert spent the first six months of 1913 on the training ship HMS Cumberland in the West Indies and on the east coast of Canada. He was rated as a midshipman aboard HMS Collingwood on 15 September 1913, and spent three months in the Mediterranean. His fellow officers gave him the nickname "Mr. Johnson". One year after his commission, he began service in the First World War. He was mentioned in despatches for his action as a turret officer aboard Collingwood in the Battle of Jutland (31 May – 1 June 1916), an indecisive engagement with the German navy that was the largest naval action of the war. He did not see further combat, largely because of ill health caused by a duodenal ulcer, for which he had an operation in November 1917.


In February 1918, he was appointed Officer in Charge of Boys at the Royal Naval Air Service's training establishment at Cranwell. With the establishment of the Royal Air Force two months later and the transfer of Cranwell from Navy to Air Force control, he transferred from the Royal Navy to the Royal Air Force. He was appointed Officer Commanding Number 4 Squadron of the Boys' Wing at Cranwell until August 1918, before reporting to the RAF's Cadet School at St Leonards-on-Sea where he completed a fortnight's training and took command of a squadron on the Cadet Wing. He was the first member of the royal family to be certified as a fully qualified pilot. During the closing weeks of the war, he served on the staff of the RAF's Independent Air Force at its headquarters in Nancy, France. Following the disbanding of the Independent Air Force in November 1918, he remained on the Continent for two months as a staff officer with the Royal Air Force until posted back to Britain. He accompanied the Belgian monarch King Albert on his triumphal reentry into Brussels on 22 November. Prince Albert qualified as an RAF pilot on 31 July 1919 and gained a promotion to squadron leader on the following day.


In October 1919, Albert went up to Trinity College, Cambridge, where he studied history, economics and civics for a year. On 4 June 1920, he was created Duke of York, Earl of Inverness and Baron Killarney. He began to take on more royal duties. He represented his father, and toured coal mines, factories, and railyards. Through such visits he acquired the nickname of the "Industrial Prince". His stammer, and his embarrassment over it, together with his tendency to shyness, caused him to appear much less impressive than his older brother, Edward. However, he was physically active and enjoyed playing tennis. He played at Wimbledon in the Men's Doubles with Louis Greig in 1926, losing in the first round. He developed an interest in working conditions, and was President of the Industrial Welfare Society. His series of annual summer camps for boys between 1921 and 1939 brought together boys from different social backgrounds.


In a time when royals were expected to marry fellow royals, it was unusual that Albert had a great deal of freedom in choosing a prospective wife. An infatuation with the already-married Australian socialite Sheila, Lady Loughborough, came to an end in April 1920 when the King, with the promise of the dukedom of York, persuaded Albert to stop seeing her. That year, he met for the first time since childhood Lady Elizabeth Bowes-Lyon, the youngest daughter of the Earl and Countess of Strathmore and Kinghorne. He became determined to marry her. She rejected his proposal twice, in 1921 and 1922, reportedly because she was reluctant to make the sacrifices necessary to become a member of the royal family. In the words of Lady Elizabeth's mother, Albert would be "made or marred" by his choice of wife. After a protracted courtship, Elizabeth agreed to marry him.


Because of his stammer, Albert dreaded public speaking. After his closing speech at the British Empire Exhibition at Wembley on 31 October 1925, one which was an ordeal for both him and his listeners, he began to see Lionel Logue, an Australian-born speech therapist. The Duke and Logue practised breathing exercises, and the Duchess rehearsed with him patiently. Subsequently, he was able to speak with less hesitation. With his delivery improved, the Duke opened the new Parliament House in Canberra, Australia, during a tour of the empire in 1927. His journey by sea to Australia, New Zealand and Fiji took him via Jamaica, where Albert played doubles tennis partnered with a black man, which was unusual at the time and taken locally as a display of equality between races.


The Duke and Duchess of York had two children: Elizabeth (called "Lilibet" by the family), and Margaret. The Duke and Duchess and their two daughters lived a relatively sheltered life at their London residence, 145 Piccadilly. They were a close and loving family. One of the few stirs arose when the Canadian Prime Minister, R. B. Bennett, considered the Duke for Governor General of Canada in 1931—a proposal that King George V rejected on the advice of the Secretary of State for Dominion Affairs, J. H. Thomas.


As Edward was unmarried and had no children, Albert was the heir presumptive to the throne. Less than a year later, on 11 December 1936, Edward VIII abdicated in order to marry his mistress, Wallis Simpson, who was divorced from her first husband and divorcing her second. Edward had been advised by British Prime Minister Stanley Baldwin that he could not remain king and marry a divorced woman with two living ex-husbands. Edward chose abdication in preference to abandoning his marriage plans. Thus Albert became king, a position he was reluctant to accept. The day before the abdication, he went to London to see his mother, Queen Mary. He wrote in his diary, "When I told her what had happened, I broke down and sobbed like a child."


On the day of the abdication, the Oireachtas, the parliament of the Irish Free State, removed all direct mention of the monarch from the Irish constitution. The next day, it passed the External Relations Act, which gave the monarch limited authority (strictly on the advice of the government) to appoint diplomatic representatives for Ireland and to be involved in the making of foreign treaties. The two acts made the Irish Free State a republic in essence without removing its links to the Commonwealth.


Albert assumed the regnal name "George VI" to emphasise continuity with his father and restore confidence in the monarchy. The beginning of George VI's reign was taken up by questions surrounding his predecessor and brother, whose titles, style and position were uncertain. He had been introduced as "His Royal Highness Prince Edward" for the abdication broadcast, but George VI felt that by abdicating and renouncing the succession Edward had lost the right to bear royal titles, including "Royal Highness". In settling the issue, George's first act as king was to confer upon his brother the title and style "His Royal Highness The Duke of Windsor", but the Letters Patent creating the dukedom prevented any wife or children from bearing royal styles. George VI was also forced to buy from Edward the royal residences of Balmoral Castle and Sandringham House, as these were private properties and did not pass to George VI automatically. Three days after his accession, on his 41st birthday, he invested his wife, the new queen consort, with the Order of the Garter.


George VI's coronation took place on 12 May 1937, the date previously intended for Edward's coronation. In a break with tradition, Queen Mary attended the ceremony in a show of support for her son. There was no Durbar held in Delhi for George VI, as had occurred for his father, as the cost would have been a burden to the government of India. Rising Indian nationalism made the welcome that the royal couple would have received likely to be muted at best, and a prolonged absence from Britain would have been undesirable in the tense period before the Second World War. Two overseas tours were undertaken, to France and to North America, both of which promised greater strategic advantages in the event of war.


The growing likelihood of war in Europe dominated the early reign of George VI. The King was constitutionally bound to support Prime Minister Neville Chamberlain's appeasement of Hitler. However, when the King and Queen greeted Chamberlain on his return from negotiating the Munich Agreement in 1938, they invited him to appear on the balcony of Buckingham Palace with them. This public association of the monarchy with a politician was exceptional, as balcony appearances were traditionally restricted to the royal family. While broadly popular among the general public, Chamberlain's policy towards Hitler was the subject of some opposition in the House of Commons, which led historian John Grigg to describe the King's behaviour in associating himself so prominently with a politician as "the most unconstitutional act by a British sovereign in the present century".


In May and June 1939, the King and Queen toured Canada and the United States. From Ottawa, the royal couple were accompanied throughout by Canadian Prime Minister William Lyon Mackenzie King, to present themselves in North America as King and Queen of Canada. George was the first reigning monarch of Canada to visit North America, although he had been to Canada previously as Prince Albert and as Duke of York. Both Governor General of Canada Lord Tweedsmuir and Mackenzie King hoped that the King's presence in Canada would demonstrate the principles of the Statute of Westminster 1931, which gave full sovereignty to the British Dominions. On 19 May, George VI personally accepted and approved the Letter of Credence of the new U.S. Ambassador to Canada, Daniel Calhoun Roper; gave Royal Assent to nine parliamentary bills; and ratified two international treaties with the Great Seal of Canada. The official royal tour historian, Gustave Lanctot, wrote "the Statute of Westminster had assumed full reality" and George gave a speech emphasising "the free and equal association of the nations of the Commonwealth".


The trip was intended to soften the strong isolationist tendencies among the North American public with regard to the developing tensions in Europe. Although the aim of the tour was mainly political, to shore up Atlantic support for the United Kingdom in any future war, the King and Queen were enthusiastically received by the public. The fear that George would be compared unfavourably to his predecessor, Edward VIII, was dispelled. They visited the 1939 New York World's Fair and stayed with President Franklin D. Roosevelt at the White House and at his private estate at Hyde Park, New York. A strong bond of friendship was forged between the King and Queen and the President during the tour, which had major significance in the relations between the United States and the United Kingdom through the ensuing war years.


In September 1939, Britain and the self-governing Dominions, but not Ireland, declared war on Nazi Germany. George VI and his wife resolved to stay in London, despite German bombing raids. They officially stayed in Buckingham Palace throughout the war, although they usually spent nights at Windsor Castle. The first German raid on London, on 7 September 1940, killed about one thousand civilians, mostly in the East End. On 13 September, the King and Queen narrowly avoided death when two German bombs exploded in a courtyard at Buckingham Palace while they were there. In defiance, the Queen famously declared: "I am glad we have been bombed. It makes me feel we can look the East End in the face". The royal family were portrayed as sharing the same dangers and deprivations as the rest of the country. They were subject to rationing restrictions, and U.S. First Lady Eleanor Roosevelt remarked on the rationed food served and the limited bathwater that was permitted during a stay at the unheated and boarded-up Palace. In August 1942, the King's brother, Prince George, Duke of Kent, was killed on active service.


In 1940, Winston Churchill replaced Neville Chamberlain as Prime Minister, though personally George would have preferred to appoint Lord Halifax. After the King's initial dismay over Churchill's appointment of Lord Beaverbrook to the Cabinet, he and Churchill developed "the closest personal relationship in modern British history between a monarch and a Prime Minister". Every Tuesday for four and a half years from September 1940, the two men met privately for lunch to discuss the war in secret and with frankness.


Throughout the war, the King and Queen provided morale-boosting visits throughout the United Kingdom, visiting bomb sites, munitions factories, and troops. The King visited military forces abroad in France in December 1939, North Africa and Malta in June 1943, Normandy in June 1944, southern Italy in July 1944, and the Low Countries in October 1944. Their high public profile and apparently indefatigable determination secured their place as symbols of national resistance. At a social function in 1944, Chief of the Imperial General Staff Sir Alan Brooke, revealed that every time he met Field Marshal Bernard Montgomery he thought he was after his job. The King replied: "You should worry, when I meet him, I always think he's after mine!"


George VI's reign saw the acceleration of the dissolution of the British Empire. The Statute of Westminster 1931 had already acknowledged the evolution of the Dominions into separate sovereign states. The process of transformation from an empire to a voluntary association of independent states, known as the Commonwealth, gathered pace after the Second World War. During the ministry of Clement Attlee, British India became the two independent dominions of India and Pakistan in 1947. George relinquished the title of Emperor of India, and became King of India and King of Pakistan instead. In 1950 he ceased to be King of India when it became a republic within the Commonwealth of Nations, but he remained King of Pakistan until his death and India recognised his new title of Head of the Commonwealth. Other countries left the Commonwealth, such as Burma in January 1948, Palestine (divided between Israel and the Arab states) in May 1948 and the Republic of Ireland in 1949.


In 1947, the King and his family toured Southern Africa. The Prime Minister of the Union of South Africa, Jan Smuts, was facing an election and hoped to make political capital out of the visit. George was appalled, however, when instructed by the South African government to shake hands only with whites, and referred to his South African bodyguards as "the Gestapo". Despite the tour, Smuts lost the election the following year, and the new government instituted a strict policy of racial segregation.


The stress of the war had taken its toll on the King's health, exacerbated by his heavy smoking and subsequent development of lung cancer among other ailments, including arteriosclerosis and thromboangiitis obliterans. A planned tour of Australia and New Zealand was postponed after the King suffered an arterial blockage in his right leg, which threatened the loss of the leg and was treated with a right lumbar sympathectomy in March 1949. His elder daughter Elizabeth, the heir presumptive, took on more royal duties as her father's health deteriorated. The delayed tour was re-organised, with Elizabeth and her husband, the Duke of Edinburgh, taking the place of the King and Queen. The King was well enough to open the Festival of Britain in May 1951, but on 23 September 1951, his left lung was removed by Clement Price Thomas after a malignant tumour was found. In October 1951, Princess Elizabeth and the Duke of Edinburgh went on a month-long tour of Canada; the trip had been delayed for a week due to the King's illness. At the State Opening of Parliament in November, the King's speech from the throne was read for him by the Lord Chancellor, Lord Simonds. His Christmas broadcast of 1951 was recorded in sections, and then edited together.


From 9 February for two days his coffin rested in St. Mary Magdalene Church, Sandringham, before lying in state at Westminster Hall from 11 February. His funeral took place at St. George's Chapel, Windsor Castle, on the 15th. He was interred initially in the Royal Vault until he was transferred to the King George VI Memorial Chapel inside St. George's on 26 March 1969. In 2002, fifty years after his death, the remains of his widow, Queen Elizabeth The Queen Mother, and the ashes of his younger daughter Princess Margaret, who both died that year, were interred in the chapel alongside him.


In the words of Labour Member of Parliament George Hardie, the abdication crisis of 1936 did "more for republicanism than fifty years of propaganda". George VI wrote to his brother Edward that in the aftermath of the abdication he had reluctantly assumed "a rocking throne", and tried "to make it steady again". He became king at a point when public faith in the monarchy was at a low ebb. During his reign his people endured the hardships of war, and imperial power was eroded. However, as a dutiful family man and by showing personal courage, he succeeded in restoring the popularity of the monarchy.


Federalism refers to the mixed or compound mode of government, combining a general government (the central or 'federal' government) with regional governments (provincial, state, Land, cantonal, territorial or other sub-unit governments) in a single political system. Its distinctive feature, exemplified in the founding example of modern federalism of the United States of America under the Constitution of 1789, is a relationship of parity between the two levels of government established. It can thus be defined as a form of government in which there is a division of powers between two levels of government of equal status.


Until recently, in the absence of prior agreement on a clear and precise definition, the concept was thought to mean (as a shorthand) 'a division of sovereignty between two levels of government'. New research, however, argues that this cannot be correct, as dividing sovereignty - when this concept is properly understood in its core meaning of the final and absolute source of political authority in a political community - is not possible. The descent of the United States into Civil War in the mid-nineteenth century, over disputes about unallocated competences concerning slavery and ultimately the right of secession, showed this. One or other level of government could be sovereign to decide such matters, but not both simultaneously. Therefore, it is now suggested that federalism is more appropriately conceived as 'a division of the powers flowing from sovereignty between two levels of government'. What differentiates the concept from other multi-level political forms is the characteristic of equality of standing between the two levels of government established. This clarified definition opens the way to identifying two distinct federal forms, where before only one was known, based upon whether sovereignty resides in the whole (in one people) or in the parts (in many peoples): the federal state (or federation) and the federal union of states (or federal union), respectively. Leading examples of the federal state include the United States, Germany, Canada, Switzerland, Australia and India. The leading example of the federal union of states is the European Union.


The terms 'federalism' and 'confederalism' both have a root in the Latin word foedus, meaning treaty, pact or covenant. Their common meaning until the late eighteenth century was a simple league or inter-governmental relationship among sovereign states based upon a treaty. They were therefore initially synonyms. It was in this sense that James Madison in Federalist 39 had referred to the new United States as 'neither a national nor a federal Constitution, but a composition of both' (ie. neither a single large unitary state nor a league/confederation among several small states, but a hybrid of the two). In the course of the nineteenth century the meaning of federalism would come to shift, strengthening to refer uniquely to the novel compound political form, while the meaning of confederalism would remain at a league of states. Thus, this article relates to the modern usage of the word 'federalism'.


Whilst it is often perceived as an optimal solution for states comprising different cultural or ethnic communities, the federalist model seems to work best in largely homogeneous states such as the United States, Germany or Australia, but there is also evidence to the contrary such as in Switzerland. Tensions between territories can still be found in federalist countries such as Canada and federation as a way to appease and quell military conflict has failed recently in places like Lybia or Iraq, while the formula is simultaneously proposed and dismissed in countries such as Ukraine or Syria. Federations such as Yugoslavia or Czechoslovakia collapsed as soon as it was possible to put the model to the test.


In the United States, federalism originally referred to belief in a stronger central government. When the U.S. Constitution was being drafted, the Federalist Party supported a stronger central government, while "Anti-Federalists" wanted a weaker central government. This is very different from the modern usage of "federalism" in Europe and the United States. The distinction stems from the fact that "federalism" is situated in the middle of the political spectrum between a confederacy and a unitary state. The U.S. Constitution was written as a reaction to the Articles of Confederation, under which the United States was a loose confederation with a weak central government.


In contrast, Europe has a greater history of unitary states than North America, thus European "federalism" argues for a weaker central government, relative to a unitary state. The modern American usage of the word is much closer to the European sense. As the power of the Federal government has increased, some people have perceived a much more unitary state than they believe the Founding Fathers intended. Most people politically advocating "federalism" in the United States argue in favor of limiting the powers of the federal government, especially the judiciary (see Federalist Society, New Federalism).


On the 1st of January 1901 the nation-state of Australia officially came into existence as a federation. The Australian continent was colonised by the United Kingdom in 1788, which subsequently established six, eventually self-governing, colonies there. In the 1890s the governments of these colonies all held referendums on becoming a unified, self-governing "Commonwealth" within the British Empire. When all the colonies voted in favour of federation, the Federation of Australia commenced, resulting in the establishment of the Commonwealth of Australia in 1901. The model of Australian federalism adheres closely to the original model of the United States of America, although it does so through a parliamentary Westminster system rather than a presidential system.


In Brazil, the fall of the monarchy in 1889 by a military coup d'état led to the rise of the presidential system, headed by Deodoro da Fonseca. Aided by well-known jurist Ruy Barbosa, Fonseca established federalism in Brazil by decree, but this system of government would be confirmed by every Brazilian constitution since 1891, although some of them would distort some of the federalist principles. The 1937 Constitution, for example, granted the federal government the authority to appoint State Governors (called interventors) at will, thus centralizing power in the hands of President Getúlio Vargas. Brazil also uses the Fonseca system to regulate interstate trade. Brazil is one of the biggest federal governments.


The government of India is based on a tiered system, in which the Constitution of India delineates the subjects on which each tier of government has executive powers. The Constitution originally provided for a two-tier system of government, the Union Government (also known as the Central Government), representing the Union of India, and the State governments. Later, a third tier was added in the form of Panchayats and Municipalities. In the current arrangement, The Seventh Schedule of the Indian Constitution delimits the subjects of each level of governmental jurisdiction, dividing them into three lists:


A distinguishing aspect of Indian federalism is that unlike many other forms of federalism, it is asymmetric. Article 370 makes special provisions for the state of Jammu and Kashmir as per its Instrument of Accession. Article 371 makes special provisions for the states of Andhra Pradesh, Arunachal Pradesh, Assam, Goa, Mizoram, Manipur, Nagaland and Sikkim as per their accession or state-hood deals. Also one more aspect of Indian federalism is system of President's Rule in which the central government (through its appointed Governor) takes control of state's administration for certain months when no party can form a government in the state or there is violent disturbance in the state.


Although the drafts of both the Maastricht treaty and the Treaty establishing a Constitution for Europe mentioned federalism, the representatives of the member countries (all of whom would have had to agree to use of the term) never formally adopted it. The strongest advocates of European federalism have been Germany, Italy, Belgium and Luxembourg while those historically most strongly opposed have been the United Kingdom, Denmark and France (with conservative presidents and governments). Since the presidency of François Mitterrand (1981-1995), the French authorities have adopted a much more pro-European Unification position, as they consider that a strong EU is presenting the best "insurance" against a unified Germany which might become too strong and thus a threat for its neighbours.


The Federal War ended in 1863 with the signing of the Treaty of Coche by both the centralist government of the time and the Federal Forces. The United States of Venezuela were subsequently incorporated under a "Federation of Sovereign States" upon principles borrowed from the Articles of Confederation of the United States of America. In this Federation, each State had a "President" of its own that controlled almost every issue, even the creation of "State Armies," while the Federal Army was required to obtain presidential permission to enter any given state.


On the other hand, Belgian federalism is federated with three components. An affirmative resolution concerning Brussels' place in the federal system passed in the parliaments of Wallonia and Brussels. These resolutions passed against the desires of Dutch-speaking parties, who are generally in favour of a federal system with two components (i.e. the Dutch and French Communities of Belgium). However, the Flemish representatives in the Parliament of the Brussels Capital-Region voted in favour of the Brussels resolution, with the exception of one party. The chairman of the Walloon Parliament stated on July 17, 2008 that, "Brussels would take an attitude". Brussels' parliament passed the resolution on July 18, 2008:


However, in order to manage the tensions present in the Spanish transition to democracy, the drafters of the current Spanish constitution avoided giving labels such as 'federal' to the territorial arrangements. Besides, unlike in the federal system, the main taxes are taken centrally from Madrid (except for the Basque Country and Navarre, which were recognized in the Spanish democratic constitution as charter territories drawing from historical reasons) and then distributed to the Autonomous Communities.


Anarchists are against the State but are not against political organization or "governance"—so long as it is self-governance utilizing direct democracy. The mode of political organization preferred by anarchists, in general, is federalism or confederalism.[citation needed] However, the anarchist definition of federalism tends to differ from the definition of federalism assumed by pro-state political scientists. The following is a brief description of federalism from section I.5 of An Anarchist FAQ:


Alternatively, or in addition to this practice, the members of an upper house may be indirectly elected by the government or legislature of the component states, as occurred in the United States prior to 1913, or be actual members or delegates of the state governments, as, for example, is the case in the German Bundesrat and in the Council of the European Union. The lower house of a federal legislature is usually directly elected, with apportionment in proportion to population, although states may sometimes still be guaranteed a certain minimum number of seats.


Federalism, and other forms of territorially autonomy, is generally seen as a useful way to structure political systems in order prevent violence among different groups with countries because it allows certain groups to legislate at the subnational level. Some scholars have suggested, however, that federalism can divide countries and result in state collapse because it creates proto-states. Still others have shown that federalism is only divisive when it lacks mechanisms tthat encourage political parties to compete across regional boundaries.


The post-Imperial nature of Russian subdivision of government changed towards a generally autonomous model which began with the establishment of the USSR (of which Russia was governed as part). It was liberalized in the aftermath of the Soviet Union, with the reforms under Boris Yeltsin preserving much of the Soviet structure while applying increasingly liberal reforms to the governance of the constituent republics and subjects (while also coming into conflict with Chechen secessionist rebels during the Chechen War). Some of the reforms under Yeltsin were scaled back by Vladimir Putin.


Federalism in the United States is the evolving relationship between state governments and the federal government of the United States. American government has evolved from a system of dual federalism to one of associative federalism. In "Federalist No. 46," James Madison asserted that the states and national government "are in fact but different agents and trustees of the people, constituted with different powers." Alexander Hamilton, writing in "Federalist No. 28," suggested that both levels of government would exercise authority to the citizens' benefit: "If their [the peoples'] rights are invaded by either, they can make use of the other as the instrument of redress." (1)


Because the states were preexisting political entities, the U.S. Constitution did not need to define or explain federalism in any one section but it often mentions the rights and responsibilities of state governments and state officials in relation to the federal government. The federal government has certain express powers (also called enumerated powers) which are powers spelled out in the Constitution, including the right to levy taxes, declare war, and regulate interstate and foreign commerce. In addition, the Necessary and Proper Clause gives the federal government the implied power to pass any law "necessary and proper" for the execution of its express powers. Other powers—the reserved powers—are reserved to the people or the states. The power delegated to the federal government was significantly expanded by the Supreme Court decision in McCulloch v. Maryland (1819), amendments to the Constitution following the Civil War, and by some later amendments—as well as the overall claim of the Civil War, that the states were legally subject to the final dictates of the federal government.


The Federalist Party of the United States was opposed by the Democratic-Republicans, including powerful figures such as Thomas Jefferson. The Democratic-Republicans mainly believed that: the Legislature had too much power (mainly because of the Necessary and Proper Clause) and that they were unchecked; the Executive had too much power, and that there was no check on the executive; a dictator would arise; and that a bill of rights should be coupled with the constitution to prevent a dictator (then believed to eventually be the president) from exploiting or tyrannizing citizens. The federalists, on the other hand, argued that it was impossible to list all the rights, and those that were not listed could be easily overlooked because they were not in the official bill of rights. Rather, rights in specific cases were to be decided by the judicial system of courts.


The meaning of federalism, as a political movement, and of what constitutes a 'federalist', varies with country and historical context.[citation needed] Movements associated with the establishment or development of federations can exhibit either centralising or decentralising trends.[citation needed] For example, at the time those nations were being established, factions known as "federalists" in the United States and Australia advocated the formation of strong central government. Similarly, in European Union politics, federalists mostly seek greater EU integration. In contrast, in Spain and in post-war Germany, federal movements have sought decentralisation: the transfer of power from central authorities to local units. In Canada, where Quebec separatism has been a political force for several decades, the "federalist" impulse aims to keep Quebec inside Canada.


From 1938 until 1995, the U.S. Supreme Court did not invalidate any federal statute as exceeding Congress' power under the Commerce Clause. Most actions by the federal government can find some legal support among the express powers, such as the Commerce Clause, whose applicability has been narrowed by the Supreme Court in recent years. In 1995 the Supreme Court rejected the Gun-Free School Zones Act in the Lopez decision, and also rejected the civil remedy portion of the Violence Against Women Act of 1994 in the United States v. Morrison decision. Recently, the Commerce Clause was interpreted to include marijuana laws in the Gonzales v. Raich decision.


On one hand, this means that the Belgian political landscape, generally speaking, consists of only two components: the Dutch-speaking population represented by Dutch-language political parties, and the majority populations of Wallonia and Brussels, represented by their French-speaking parties. The Brussels region emerges as a third component. This specific dual form of federalism, with the special position of Brussels, consequently has a number of political issues—even minor ones—that are being fought out over the Dutch/French-language political division. With such issues, a final decision is possible only in the form of a compromise. This tendency gives this dual federalism model a number of traits that generally are ascribed to confederalism, and makes the future of Belgian federalism contentious.


Some federal constitutions also provide that certain constitutional amendments cannot occur without the unanimous consent of all states or of a particular state. The US constitution provides that no state may be deprived of equal representation in the senate without its consent. In Australia, if a proposed amendment will specifically impact one or more states, then it must be endorsed in the referendum held in each of those states. Any amendment to the Canadian constitution that would modify the role of the monarchy would require unanimous consent of the provinces. The German Basic Law provides that no amendment is admissible at all that would abolish the federal system.


Where every component state of a federation possesses the same powers, we are said to find 'symmetric federalism'. Asymmetric federalism exists where states are granted different powers, or some possess greater autonomy than others do. This is often done in recognition of the existence of a distinct culture in a particular region or regions. In Spain, the Basques and Catalans, as well as the Galicians, spearheaded a historic movement to have their national specificity recognized, crystallizing in the "historical communities" such as Navarre, Galicia, Catalonia, and the Basque Country. They have more powers than the later expanded arrangement for other Spanish regions, or the Spain of the autonomous communities (called also the "coffee for everyone" arrangement), partly to deal with their separate identity and to appease peripheral nationalist leanings, partly out of respect to specific rights they had held earlier in history. However, strictly speaking Spain is not a federalism, but a decentralized administrative organization of the state.


Federations often have special procedures for amendment of the federal constitution. As well as reflecting the federal structure of the state this may guarantee that the self-governing status of the component states cannot be abolished without their consent. An amendment to the constitution of the United States must be ratified by three-quarters of either the state legislatures, or of constitutional conventions specially elected in each of the states, before it can come into effect. In referendums to amend the constitutions of Australia and Switzerland it is required that a proposal be endorsed not just by an overall majority of the electorate in the nation as a whole, but also by separate majorities in each of a majority of the states or cantons. In Australia, this latter requirement is known as a double majority.


The structures of most federal governments incorporate mechanisms to protect the rights of component states. One method, known as 'intrastate federalism', is to directly represent the governments of component states in federal political institutions. Where a federation has a bicameral legislature the upper house is often used to represent the component states while the lower house represents the people of the nation as a whole. A federal upper house may be based on a special scheme of apportionment, as is the case in the senates of the United States and Australia, where each state is represented by an equal number of senators irrespective of the size of its population.


Federations often employ the paradox of being a union of states, while still being states (or having aspects of statehood) in themselves. For example, James Madison (author of the US Constitution) wrote in Federalist Paper No. 39 that the US Constitution "is in strictness neither a national nor a federal constitution; but a composition of both. In its foundation, it is federal, not national; in the sources from which the ordinary powers of the Government are drawn, it is partly federal, and partly national..." This stems from the fact that states in the US maintain all sovereignty that they do not yield to the federation by their own consent. This was reaffirmed by the Tenth Amendment to the United States Constitution, which reserves all powers and rights that are not delegated to the Federal Government as left to the States and to the people.


Usually, a federation is formed at two levels: the central government and the regions (states, provinces, territories), and little to nothing is said about second or third level administrative political entities. Brazil is an exception, because the 1988 Constitution included the municipalities as autonomous political entities making the federation tripartite, encompassing the Union, the States, and the municipalities. Each state is divided into municipalities (municípios) with their own legislative council (câmara de vereadores) and a mayor (prefeito), which are partly autonomous from both Federal and State Government. Each municipality has a "little constitution", called "organic law" (lei orgânica). Mexico is an intermediate case, in that municipalities are granted full-autonomy by the federal constitution and their existence as autonomous entities (municipio libre, "free municipality") is established by the federal government and cannot be revoked by the states' constitutions. Moreover, the federal constitution determines which powers and competencies belong exclusively to the municipalities and not to the constituent states. However, municipalities do not have an elected legislative assembly.


China is the largest unitary state in the world by both population and land area. Although China has had long periods of central rule for centuries, it is often argued that the unitary structure of the Chinese government is far too unwieldy to effectively and equitably manage the country's affairs. On the other hand, Chinese nationalists are suspicious of decentralization as a form of secessionism and a backdoor for national disunity; still others argue that the degree of autonomy given to provincial-level officials in the People's Republic of China amounts to a de facto federalism.


The Philippines is a unitary state with some powers devolved to Local Government Units (LGUs) under the terms of the Local Government Code. There is also one autonomous region, the Autonomous Region of Muslim Mindanao. Over the years various modifications have been proposed to the Constitution of the Philippines, including possible transition to a federal system as part of a shift to a parliamentary system. In 2004, Philippine President Gloria Macapagal Arroyo established the Consultative Commission which suggested such a Charter Change but no action was taken by the Philippine Congress to amend the 1987 Constitution.


Spain is a unitary state with a high level of decentralisation, often regarded as a federal system in all but name or a "federation without federalism". The country has been quoted as being "an extraordinarily decentralized country", with the central government accounting for just 18% of public spending, 38% for the regional governments, 13% for the local councils, and the remaining 31% for the social security system. The current Spanish constitution has been implemented in such a way that, in many respects, Spain can be compared to countries which are undeniably federal.


The United Kingdom has traditionally been governed as a unitary state by the Westminster Parliament in London. Instead of adopting a federal model, the UK has relied on gradual devolution to decentralise political power. Devolution in the UK began with the Government of Ireland Act 1914 which granted home rule to Ireland as a constituent country of the former United Kingdom of Great Britain and Ireland. Following the partition of Ireland in 1921 which saw the creation of the sovereign Irish Free State (which eventually evolved into the modern day Republic of Ireland), Northern Ireland retained its devolved government through the Parliament of Northern Ireland, the only part of the UK to have such a body at this time. This body was suspended in 1972 and Northern Ireland was governed by direct rule during the period of conflict known as The Troubles.


In modern times, a process of devolution in the United Kingdom has decentralised power once again. Since the 1997 referendums in Scotland and Wales and the Good Friday Agreement in Northern Ireland, three of the four constituent countries of the UK now have some level of autonomy. Government has been devolved to the Scottish Parliament, the National Assembly for Wales and the Northern Ireland Assembly. England does not have its own parliament and English affairs continue to be decided by the Westminster Parliament. In 1998 a set of eight unelected Regional assemblies, or chambers, was created to support the English Regional Development Agencies, but these were abolished between 2008 and 2010. The Regions of England continue to be used in certain governmental administrative functions.


Federalism also finds expression in ecclesiology (the doctrine of the church). For example, presbyterian church governance resembles parliamentary republicanism (a form of political federalism) to a large extent. In Presbyterian denominations, the local church is ruled by elected elders, some of which are ministerial. Each church then sends representatives or commissioners to presbyteries and further to a general assembly. Each greater level of assembly has ruling authority over its constituent members. In this governmental structure, each component has some level of sovereignty over itself. As in political federalism, in presbyterian ecclesiology there is shared sovereignty.


Some Christians argue that the earliest source of political federalism (or federalism in human institutions; in contrast to theological federalism) is the ecclesiastical federalism found in the Bible. They point to the structure of the early Christian Church as described (and prescribed, as believed by many) in the New Testament. In their arguments, this is particularly demonstrated in the Council of Jerusalem, described in Acts chapter 15, where the Apostles and elders gathered together to govern the Church; the Apostles being representatives of the universal Church, and elders being such for the local church. To this day, elements of federalism can be found in almost every Christian denomination, some more than others.


In almost all federations the central government enjoys the powers of foreign policy and national defense as exclusive federal powers. Were this not the case a federation would not be a single sovereign state, per the UN definition. Notably, the states of Germany retain the right to act on their own behalf at an international level, a condition originally granted in exchange for the Kingdom of Bavaria's agreement to join the German Empire in 1871. Beyond this the precise division of power varies from one nation to another. The constitutions of Germany and the United States provide that all powers not specifically granted to the federal government are retained by the states. The Constitution of some countries like Canada and India, on the other hand, state that powers not explicitly granted to the provincial governments are retained by the federal government. Much like the US system, the Australian Constitution allocates to the Federal government (the Commonwealth of Australia) the power to make laws about certain specified matters which were considered too difficult for the States to manage, so that the States retain all other areas of responsibility. Under the division of powers of the European Union in the Lisbon Treaty, powers which are not either exclusively of European competence or shared between EU and state as concurrent powers are retained by the constituent states.


The annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of polychaetes. Annelids are considered members of the Lophotrochozoa, a "super-phylum" of protostomes that also includes molluscs, brachiopods, flatworms and nemerteans.


The basic annelid form consists of multiple segments. Each segment has the same sets of organs and, in most polychaetes, has a pair of parapodia that many species use for locomotion. Septa separate the segments of many species, but are poorly defined or absent in others, and Echiura and Sipuncula show no obvious signs of segmentation. In species with well-developed septa, the blood circulates entirely within blood vessels, and the vessels in segments near the front ends of these species are often built up with muscles that act as hearts. The septa of such species also enable them to change the shapes of individual segments, which facilitates movement by peristalsis ("ripples" that pass along the body) or by undulations that improve the effectiveness of the parapodia. In species with incomplete septa or none, the blood circulates through the main body cavity without any kind of pump, and there is a wide range of locomotory techniques – some burrowing species turn their pharynges inside out to drag themselves through the sediment.


Although many species can reproduce asexually and use similar mechanisms to regenerate after severe injuries, sexual reproduction is the normal method in species whose reproduction has been studied. The minority of living polychaetes whose reproduction and lifecycles are known produce trochophore larvae, that live as plankton and then sink and metamorphose into miniature adults. Oligochaetes are full hermaphrodites and produce a ring-like cocoon around their bodies, in which the eggs and hatchlings are nourished until they are ready to emerge.


Earthworms are Oligochaetes that support terrestrial food chains both as prey and in some regions are important in aeration and enriching of soil. The burrowing of marine polychaetes, which may constitute up to a third of all species in near-shore environments, encourages the development of ecosystems by enabling water and oxygen to penetrate the sea floor. In addition to improving soil fertility, annelids serve humans as food and as bait. Scientists observe annelids to monitor the quality of marine and fresh water. Although blood-letting is no longer in favor with doctors, some leech species are regarded as endangered species because they have been over-harvested for this purpose in the last few centuries. Ragworms' jaws are now being studied by engineers as they offer an exceptional combination of lightness and strength.


Since annelids are soft-bodied, their fossils are rare – mostly jaws and the mineralized tubes that some of the species secreted. Although some late Ediacaran fossils may represent annelids, the oldest known fossil that is identified with confidence comes from about 518 million years ago in the early Cambrian period. Fossils of most modern mobile polychaete groups appeared by the end of the Carboniferous, about 299 million years ago. Palaeontologists disagree about whether some body fossils from the mid Ordovician, about 472 to 461 million years ago, are the remains of oligochaetes, and the earliest indisputable fossils of the group appear in the Tertiary period, which began 65 million years ago.


No single feature distinguishes Annelids from other invertebrate phyla, but they have a distinctive combination of features. Their bodies are long, with segments that are divided externally by shallow ring-like constrictions called annuli and internally by septa ("partitions") at the same points, although in some species the septa are incomplete and in a few cases missing. Most of the segments contain the same sets of organs, although sharing a common gut, circulatory system and nervous system makes them inter-dependent. Their bodies are covered by a cuticle (outer covering) that does not contain cells but is secreted by cells in the skin underneath, is made of tough but flexible collagen and does not molt – on the other hand arthropods' cuticles are made of the more rigid α-chitin, and molt until the arthropods reach their full size. Most annelids have closed circulatory systems, where the blood makes its entire circuit via blood vessels.


Most of an annelid's body consists of segments that are practically identical, having the same sets of internal organs and external chaetae (Greek χαιτη, meaning "hair") and, in some species, appendages. However, the frontmost and rearmost sections are not regarded as true segments as they do not contain the standard sets of organs and do not develop in the same way as the true segments. The frontmost section, called the prostomium (Greek προ- meaning "in front of" and στομα meaning "mouth") contains the brain and sense organs, while the rearmost, called the pygidium (Greek πυγιδιον, meaning "little tail") or periproct contains the anus, generally on the underside. The first section behind the prostomium, called the peristomium (Greek περι- meaning "around" and στομα meaning "mouth"), is regarded by some zoologists as not a true segment, but in some polychaetes the peristomium has chetae and appendages like those of other segments.


Annelids' cuticles are made of collagen fibers, usually in layers that spiral in alternating directions so that the fibers cross each other. These are secreted by the one-cell deep epidermis (outermost skin layer). A few marine annelids that live in tubes lack cuticles, but their tubes have a similar structure, and mucus-secreting glands in the epidermis protect their skins. Under the epidermis is the dermis, which is made of connective tissue, in other words a combination of cells and non-cellular materials such as collagen. Below this are two layers of muscles, which develop from the lining of the coelom (body cavity): circular muscles make a segment longer and slimmer when they contract, while under them are longitudinal muscles, usually four distinct strips, whose contractions make the segment shorter and fatter. Some annelids also have oblique internal muscles that connect the underside of the body to each side.


The setae ("hairs") of annelids project out from the epidermis to provide traction and other capabilities. The simplest are unjointed and form paired bundles near the top and bottom of each side of each segment. The parapodia ("limbs") of annelids that have them often bear more complex chetae at their tips – for example jointed, comb-like or hooked. Chetae are made of moderately flexible β-chitin and are formed by follicles, each of which has a chetoblast ("hair-forming") cell at the bottom and muscles that can extend or retract the cheta. The chetoblasts produce chetae by forming microvilli, fine hair-like extensions that increase the area available for secreting the cheta. When the cheta is complete, the microvilli withdraw into the chetoblast, leaving parallel tunnels that run almost the full length of the cheta. Hence annelids' chetae are structurally different from the setae ("bristles") of arthropods, which are made of the more rigid α-chitin, have a single internal cavity, and are mounted on flexible joints in shallow pits in the cuticle.


Nearly all polychaetes have parapodia that function as limbs, while other major annelid groups lack them. Parapodia are unjointed paired extensions of the body wall, and their muscles are derived from the circular muscles of the body. They are often supported internally by one or more large, thick chetae. The parapodia of burrowing and tube-dwelling polychaetes are often just ridges whose tips bear hooked chetae. In active crawlers and swimmers the parapodia are often divided into large upper and lower paddles on a very short trunk, and the paddles are generally fringed with chetae and sometimes with cirri (fused bundles of cilia) and gills.


The brain generally forms a ring round the pharynx (throat), consisting of a pair of ganglia (local control centers) above and in front of the pharynx, linked by nerve cords either side of the pharynx to another pair of ganglia just below and behind it. The brains of polychaetes are generally in the prostomium, while those of clitellates are in the peristomium or sometimes the first segment behind the peristomium. In some very mobile and active polychaetes the brain is enlarged and more complex, with visible hindbrain, midbrain and forebrain sections. The rest of the central nervous system is generally "ladder-like", consisting of a pair of nerve cords that run through the bottom part of the body and have in each segment paired ganglia linked by a transverse connection. From each segmental ganglion a branching system of local nerves runs into the body wall and then encircles the body. However, in most polychaetes the two main nerve cords are fused, and in the tube-dwelling genus Owenia the single nerve chord has no ganglia and is located in the epidermis.


As in arthropods, each muscle fiber (cell) is controlled by more than one neuron, and the speed and power of the fiber's contractions depends on the combined effects of all its neurons. Vertebrates have a different system, in which one neuron controls a group of muscle fibers. Most annelids' longitudinal nerve trunks include giant axons (the output signal lines of nerve cells). Their large diameter decreases their resistance, which allows them to transmit signals exceptionally fast. This enables these worms to withdraw rapidly from danger by shortening their bodies. Experiments have shown that cutting the giant axons prevents this escape response but does not affect normal movement.


The sensors are primarily single cells that detect light, chemicals, pressure waves and contact, and are present on the head, appendages (if any) and other parts of the body. Nuchal ("on the neck") organs are paired, ciliated structures found only in polychaetes, and are thought to be chemosensors. Some polychaetes also have various combinations of ocelli ("little eyes") that detect the direction from which light is coming and camera eyes or compound eyes that can probably form images. The compound eyes probably evolved independently of arthropods' eyes. Some tube-worms use ocelli widely spread over their bodies to detect the shadows of fish, so that they can quickly withdraw into their tubes. Some burrowing and tube-dwelling polychaetes have statocysts (tilt and balance sensors) that tell them which way is down. A few polychaete genera have on the undersides of their heads palps that are used both in feeding and as "feelers", and some of these also have antennae that are structurally similar but probably are used mainly as "feelers".


Most annelids have a pair of coelomata (body cavities) in each segment, separated from other segments by septa and from each other by vertical mesenteries. Each septum forms a sandwich with connective tissue in the middle and mesothelium (membrane that serves as a lining) from the preceding and following segments on either side. Each mesentery is similar except that the mesothelium is the lining of each of the pair of coelomata, and the blood vessels and, in polychaetes, the main nerve cords are embedded in it. The mesothelium is made of modified epitheliomuscular cells; in other words, their bodies form part of the epithelium but their bases extend to form muscle fibers in the body wall. The mesothelium may also form radial and circular muscles on the septa, and circular muscles around the blood vessels and gut. Parts of the mesothelium, especially on the outside of the gut, may also form chloragogen cells that perform similar functions to the livers of vertebrates: producing and storing glycogen and fat; producing the oxygen-carrier hemoglobin; breaking down proteins; and turning nitrogenous waste products into ammonia and urea to be excreted.


Many annelids move by peristalsis (waves of contraction and expansion that sweep along the body), or flex the body while using parapodia to crawl or swim. In these animals the septa enable the circular and longitudinal muscles to change the shape of individual segments, by making each segment a separate fluid-filled "balloon". However, the septa are often incomplete in annelids that are semi-sessile or that do not move by peristalsis or by movements of parapodia – for example some move by whipping movements of the body, some small marine species move by means of cilia (fine muscle-powered hairs) and some burrowers turn their pharynges (throats) inside out to penetrate the sea-floor and drag themselves into it.


The fluid in the coelomata contains coelomocyte cells that defend the animals against parasites and infections. In some species coelomocytes may also contain a respiratory pigment – red hemoglobin in some species, green chlorocruorin in others (dissolved in the plasma) – and provide oxygen transport within their segments. Respiratory pigment is also dissolved in the blood plasma. Species with well-developed septa generally also have blood vessels running all long their bodies above and below the gut, the upper one carrying blood forwards while the lower one carries it backwards. Networks of capillaries in the body wall and around the gut transfer blood between the main blood vessels and to parts of the segment that need oxygen and nutrients. Both of the major vessels, especially the upper one, can pump blood by contracting. In some annelids the forward end of the upper blood vessel is enlarged with muscles to form a heart, while in the forward ends of many earthworms some of the vessels that connect the upper and lower main vessels function as hearts. Species with poorly developed or no septa generally have no blood vessels and rely on the circulation within the coelom for delivering nutrients and oxygen.


However, leeches and their closest relatives have a body structure that is very uniform within the group but significantly different from that of other annelids, including other members of the Clitellata. In leeches there are no septa, the connective tissue layer of the body wall is so thick that it occupies much of the body, and the two coelomata are widely separated and run the length of the body. They function as the main blood vessels, although they are side-by-side rather than upper and lower. However, they are lined with mesothelium, like the coelomata and unlike the blood vessels of other annelids. Leeches generally use suckers at their front and rear ends to move like inchworms. The anus is on the upper surface of the pygidium.


Feeding structures in the mouth region vary widely, and have little correlation with the animals' diets. Many polychaetes have a muscular pharynx that can be everted (turned inside out to extend it). In these animals the foremost few segments often lack septa so that, when the muscles in these segments contract, the sharp increase in fluid pressure from all these segments everts the pharynx very quickly. Two families, the Eunicidae and Phyllodocidae, have evolved jaws, which can be used for seizing prey, biting off pieces of vegetation, or grasping dead and decaying matter. On the other hand, some predatory polychaetes have neither jaws nor eversible pharynges. Selective deposit feeders generally live in tubes on the sea-floor and use palps to find food particles in the sediment and then wipe them into their mouths. Filter feeders use "crowns" of palps covered in cilia that wash food particles towards their mouths. Non-selective deposit feeders ingest soil or marine sediments via mouths that are generally unspecialized. Some clitellates have sticky pads in the roofs of their mouths, and some of these can evert the pads to capture prey. Leeches often have an eversible proboscis, or a muscular pharynx with two or three teeth.


The gut is generally an almost straight tube supported by the mesenteries (vertical partitions within segments), and ends with the anus on the underside of the pygidium. However, in members of the tube-dwelling family Siboglinidae the gut is blocked by a swollen lining that houses symbiotic bacteria, which can make up 15% of the worms' total weight. The bacteria convert inorganic matter – such as hydrogen sulfide and carbon dioxide from hydrothermal vents, or methane from seeps – to organic matter that feeds themselves and their hosts, while the worms extend their palps into the gas flows to absorb the gases needed by the bacteria.


Annelids with blood vessels use metanephridia to remove soluble waste products, while those without use protonephridia. Both of these systems use a two-stage filtration process, in which fluid and waste products are first extracted and these are filtered again to re-absorb any re-usable materials while dumping toxic and spent materials as urine. The difference is that protonephridia combine both filtration stages in the same organ, while metanephridia perform only the second filtration and rely on other mechanisms for the first – in annelids special filter cells in the walls of the blood vessels let fluids and other small molecules pass into the coelomic fluid, where it circulates to the metanephridia. In annelids the points at which fluid enters the protonephridia or metanephridia are on the forward side of a septum while the second-stage filter and the nephridiopore (exit opening in the body wall) are in the following segment. As a result, the hindmost segment (before the growth zone and pygidium) has no structure that extracts its wastes, as there is no following segment to filter and discharge them, while the first segment contains an extraction structure that passes wastes to the second, but does not contain the structures that re-filter and discharge urine.


It is thought that annelids were originally animals with two separate sexes, which released ova and sperm into the water via their nephridia. The fertilized eggs develop into trochophore larvae, which live as plankton. Later they sink to the sea-floor and metamorphose into miniature adults: the part of the trochophore between the apical tuft and the prototroch becomes the prostomium (head); a small area round the trochophore's anus becomes the pygidium (tail-piece); a narrow band immediately in front of that becomes the growth zone that produces new segments; and the rest of the trochophore becomes the peristomium (the segment that contains the mouth).


However, the lifecycles of most living polychaetes, which are almost all marine animals, are unknown, and only about 25% of the 300+ species whose lifecycles are known follow this pattern. About 14% use a similar external fertilization but produce yolk-rich eggs, which reduce the time the larva needs to spend among the plankton, or eggs from which miniature adults emerge rather than larvae. The rest care for the fertilized eggs until they hatch – some by producing jelly-covered masses of eggs which they tend, some by attaching the eggs to their bodies and a few species by keeping the eggs within their bodies until they hatch. These species use a variety of methods for sperm transfer; for example, in some the females collect sperm released into the water, while in others the males have a penis that inject sperm into the female. There is no guarantee that this is a representative sample of polychaetes' reproductive patterns, and it simply reflects scientists' current knowledge.


Some polychaetes breed only once in their lives, while others breed almost continuously or through several breeding seasons. While most polychaetes remain of one sex all their lives, a significant percentage of species are full hermaphrodites or change sex during their lives. Most polychaetes whose reproduction has been studied lack permanent gonads, and it is uncertain how they produce ova and sperm. In a few species the rear of the body splits off and becomes a separate individual that lives just long enough to swim to a suitable environment, usually near the surface, and spawn.


Most mature clitellates (the group that includes earthworms and leeches) are full hermaphrodites, although in a few leech species younger adults function as males and become female at maturity. All have well-developed gonads, and all copulate. Earthworms store their partners' sperm in spermathecae ("sperm stores") and then the clitellum produces a cocoon that collects ova from the ovaries and then sperm from the spermathecae. Fertilization and development of earthworm eggs takes place in the cocoon. Leeches' eggs are fertilized in the ovaries, and then transferred to the cocoon. In all clitellates the cocoon also either produces yolk when the eggs are fertilized or nutrients while they are developing. All clitellates hatch as miniature adults rather than larvae.


Charles Darwin's book The Formation of Vegetable Mould through the Action of Worms (1881) presented the first scientific analysis of earthworms' contributions to soil fertility. Some burrow while others live entirely on the surface, generally in moist leaf litter. The burrowers loosen the soil so that oxygen and water can penetrate it, and both surface and burrowing worms help to produce soil by mixing organic and mineral matter, by accelerating the decomposition of organic matter and thus making it more quickly available to other organisms, and by concentrating minerals and converting them to forms that plants can use more easily. Earthworms are also important prey for birds ranging in size from robins to storks, and for mammals ranging from shrews to badgers, and in some cases conserving earthworms may be essential for conserving endangered birds.


Terrestrial annelids can be invasive in some situations. In the glaciated areas of North America, for example, almost all native earthworms are thought to have been killed by the glaciers and the worms currently found in those areas are all introduced from other areas, primarily from Europe, and, more recently, from Asia. Northern hardwood forests are especially negatively impacted by invasive worms through the loss of leaf duff, soil fertility, changes in soil chemistry and the loss of ecological diversity. Especially of concern is Amynthas agrestis and at least one state (Wisconsin) has listed it as a prohibited species.


Earthworms make a significant contribution to soil fertility. The rear end of the Palolo worm, a marine polychaete that tunnels through coral, detaches in order to spawn at the surface, and the people of Samoa regard these spawning modules as a delicacy. Anglers sometimes find that worms are more effective bait than artificial flies, and worms can be kept for several days in a tin lined with damp moss. Ragworms are commercially important as bait and as food sources for aquaculture, and there have been proposals to farm them in order to reduce over-fishing of their natural populations. Some marine polychaetes' predation on molluscs causes serious losses to fishery and aquaculture operations.


Accounts of the use of leeches for the medically dubious practise of blood-letting have come from China around 30 AD, India around 200 AD, ancient Rome around 50 AD and later throughout Europe. In the 19th century medical demand for leeches was so high that some areas' stocks were exhausted and other regions imposed restrictions or bans on exports, and Hirudo medicinalis is treated as an endangered species by both IUCN and CITES. More recently leeches have been used to assist in microsurgery, and their saliva has provided anti-inflammatory compounds and several important anticoagulants, one of which also prevents tumors from spreading.


Since annelids are soft-bodied, their fossils are rare. Polychaetes' fossil record consists mainly of the jaws that some species had and the mineralized tubes that some secreted. Some Ediacaran fossils such as Dickinsonia in some ways resemble polychaetes, but the similarities are too vague for these fossils to be classified with confidence. The small shelly fossil Cloudina, from 549 to 542 million years ago, has been classified by some authors as an annelid, but by others as a cnidarian (i.e. in the phylum to which jellyfish and sea anemones belong). Until 2008 the earliest fossils widely accepted as annelids were the polychaetes Canadia and Burgessochaeta, both from Canada's Burgess Shale, formed about 505 million years ago in the early Cambrian. Myoscolex, found in Australia and a little older than the Burgess Shale, was possibly an annelid. However, it lacks some typical annelid features and has features which are not usually found in annelids and some of which are associated with other phyla. Then Simon Conway Morris and John Peel reported Phragmochaeta from Sirius Passet, about 518 million years old, and concluded that it was the oldest annelid known to date. There has been vigorous debate about whether the Burgess Shale fossil Wiwaxia was a mollusc or an annelid. Polychaetes diversified in the early Ordovician, about 488 to 474 million years ago. It is not until the early Ordovician that the first annelid jaws are found, thus the crown-group cannot have appeared before this date and probably appeared somewhat later. By the end of the Carboniferous, about 299 million years ago, fossils of most of the modern mobile polychaete groups had appeared. Many fossil tubes look like those made by modern sessile polychaetes  , but the first tubes clearly produced by polychaetes date from the Jurassic, less than 199 million years ago.


The earliest good evidence for oligochaetes occurs in the Tertiary period, which began 65 million years ago, and it has been suggested that these animals evolved around the same time as flowering plants in the early Cretaceous, from 130 to 90 million years ago. A trace fossil consisting of a convoluted burrow partly filled with small fecal pellets may be evidence that earthworms were present in the early Triassic period from 251 to 245 million years ago. Body fossils going back to the mid Ordovician, from 472 to 461 million years ago, have been tentatively classified as oligochaetes, but these identifications are uncertain and some have been disputed.


Traditionally the annelids have been divided into two major groups, the polychaetes and clitellates. In turn the clitellates were divided into oligochaetes, which include earthworms, and hirudinomorphs, whose best-known members are leeches. For many years there was no clear arrangement of the approximately 80 polychaete families into higher-level groups. In 1997 Greg Rouse and Kristian Fauchald attempted a "first heuristic step in terms of bringing polychaete systematics to an acceptable level of rigour", based on anatomical structures, and divided polychaetes into:


In 2007 Torsten Struck and colleagues compared 3 genes in 81 taxa, of which 9 were outgroups, in other words not considered closely related to annelids but included to give an indication of where the organisms under study are placed on the larger tree of life. For a cross-check the study used an analysis of 11 genes (including the original 3) in 10 taxa. This analysis agreed that clitellates, pogonophorans and echiurans were on various branches of the polychaete family tree. It also concluded that the classification of polychaetes into Scolecida, Canalipalpata and Aciculata was useless, as the members of these alleged groups were scattered all over the family tree derived from comparing the 81 taxa. In addition, it also placed sipunculans, generally regarded at the time as a separate phylum, on another branch of the polychaete tree, and concluded that leeches were a sub-group of oligochaetes rather than their sister-group among the clitellates. Rouse accepted the analyses based on molecular phylogenetics, and their main conclusions are now the scientific consensus, although the details of the annelid family tree remain uncertain.


In addition to re-writing the classification of annelids and 3 previously independent phyla, the molecular phylogenetics analyses undermine the emphasis that decades of previous writings placed on the importance of segmentation in the classification of invertebrates. Polychaetes, which these analyses found to be the parent group, have completely segmented bodies, while polychaetes' echiurans and sipunculan offshoots are not segmented and pogonophores are segmented only in the rear parts of their bodies. It now seems that segmentation can appear and disappear much more easily in the course of evolution than was previously thought. The 2007 study also noted that the ladder-like nervous system, which is associated with segmentation, is less universal previously thought in both annelids and arthropods.[n 2]


Annelids are members of the protostomes, one of the two major superphyla of bilaterian animals – the other is the deuterostomes, which includes vertebrates. Within the protostomes, annelids used to be grouped with arthropods under the super-group Articulata ("jointed animals"), as segmentation is obvious in most members of both phyla. However, the genes that drive segmentation in arthropods do not appear to do the same in annelids. Arthropods and annelids both have close relatives that are unsegmented. It is at least as easy to assume that they evolved segmented bodies independently as it is to assume that the ancestral protostome or bilaterian was segmented and that segmentation disappeared in many descendant phyla. The current view is that annelids are grouped with molluscs, brachiopods and several other phyla that have lophophores (fan-like feeding structures) and/or trochophore larvae as members of Lophotrochozoa. Bryzoa may be the most basal phylum (the one that first became distinctive) within the Lophotrochozoa, and the relationships between the other members are not yet known. Arthropods are now regarded as members of the Ecdysozoa ("animals that molt"), along with some phyla that are unsegmented.


The "Lophotrochozoa" hypothesis is also supported by the fact that many phyla within this group, including annelids, molluscs, nemerteans and flatworms, follow a similar pattern in the fertilized egg's development. When their cells divide after the 4-cell stage, descendants of these 4 cells form a spiral pattern. In these phyla the "fates" of the embryo's cells, in other words the roles their descendants will play in the adult animal, are the same and can be predicted from a very early stage. Hence this development pattern is often described as "spiral determinate cleavage".


In monotheism and henotheism, God is conceived of as the Supreme Being and principal object of faith. The concept of God as described by theologians commonly includes the attributes of omniscience (infinite knowledge), omnipotence (unlimited power), omnipresence (present everywhere), omnibenevolence (perfect goodness), divine simplicity, and eternal and necessary existence. God is also usually defined as a non-corporeal being without any human biological gender, but the concept of God actively (as opposed to receptively) creating the universe has caused some religions to give "Him" the metaphorical name of "Father". Because God is conceived as not being a corporeal being, God cannot(some say should not) be portrayed in a literal visual image; some religious groups use a man (sometimes old and bearded) to symbolize God because of His deed of creating man's mind in the image of His own.


In theism, God is the creator and sustainer of the universe, while in deism, God is the creator, but not the sustainer, of the universe. Monotheism is the belief in the existence of one God or in the oneness of God. In pantheism, God is the universe itself. In atheism, God is not believed to exist, while God is deemed unknown or unknowable within the context of agnosticism. God has also been conceived as being incorporeal (immaterial), a personal being, the source of all moral obligation, and the "greatest conceivable existent". Many notable philosophers have developed arguments for and against the existence of God.


There are many names for God, and different names are attached to different cultural ideas about God's identity and attributes. In the ancient Egyptian era of Atenism, possibly the earliest recorded monotheistic religion, this deity was called Aten, premised on being the one "true" Supreme Being and Creator of the Universe. In the Hebrew Bible and Judaism, "He Who Is", "I Am that I Am", and the tetragrammaton YHWH are used as names of God, while Yahweh and Jehovah are sometimes used in Christianity as vocalizations of YHWH. In the Christian doctrine of the Trinity, God, consubstantial in three persons, is called the Father, the Son, and the Holy Spirit. In Judaism, it is common to refer to God by the titular names Elohim or Adonai, the latter of which is believed by some scholars to descend from the Egyptian Aten. In Islam, the name Allah, "Al-El", or "Al-Elah" ("the God") is used, while Muslims also have a multitude of titular names for God. In Hinduism, Brahman is often considered a monistic deity. Other religions have names for God, for instance, Baha in the Bahá'í Faith, Waheguru in Sikhism, and Ahura Mazda in Zoroastrianism.


The earliest written form of the Germanic word God (always, in this usage, capitalized) comes from the 6th-century Christian Codex Argenteus. The English word itself is derived from the Proto-Germanic * ǥuđan. The reconstructed Proto-Indo-European form * ǵhu-tó-m was likely based on the root * ǵhau(ə)-, which meant either "to call" or "to invoke". The Germanic words for God were originally neuter—applying to both genders—but during the process of the Christianization of the Germanic peoples from their indigenous Germanic paganism, the words became a masculine syntactic form.


In the English language, the capitalized form of God continues to represent a distinction between monotheistic "God" and "gods" in polytheism. The English word God and its counterparts in other languages are normally used for any and all conceptions and, in spite of significant differences between religions, the term remains an English translation common to all. The same holds for Hebrew El, but in Judaism, God is also given a proper name, the tetragrammaton YHWH, in origin possibly the name of an Edomite or Midianite deity, Yahweh. In many translations of the Bible, when the word LORD is in all capitals, it signifies that the word represents the tetragrammaton.


There is no clear consensus on the nature or even the existence of God. The Abrahamic conceptions of God include the monotheistic definition of God in Judaism, the trinitarian view of Christians, and the Islamic concept of God. The dharmic religions differ in their view of the divine: views of God in Hinduism vary by region, sect, and caste, ranging from monotheistic to polytheistic to atheistic. Divinity was recognized by the historical Buddha, particularly Śakra and Brahma. However, other sentient beings, including gods, can at best only play a supportive role in one's personal path to salvation. Conceptions of God in the latter developments of the Mahayana tradition give a more prominent place to notions of the divine.[citation needed]


Monotheists hold that there is only one god, and may claim that the one true god is worshiped in different religions under different names. The view that all theists actually worship the same god, whether they know it or not, is especially emphasized in Hinduism and Sikhism. In Christianity, the doctrine of the Trinity describes God as one God in three persons. The Trinity comprises God the Father, God the Son (Jesus), and God the Holy Spirit. Islam's most fundamental concept is tawhid (meaning "oneness" or "uniqueness"). God is described in the Quran as: "Say: He is Allah, the One and Only; Allah, the Eternal, Absolute; He begetteth not, nor is He begotten; And there is none like unto Him." Muslims repudiate the Christian doctrine of the Trinity and divinity of Jesus, comparing it to polytheism. In Islam, God is beyond all comprehension or equal and does not resemble any of his creations in any way. Thus, Muslims are not iconodules, and are not expected to visualize God.