The Ann Arbor News, owned by the Michigan-based Booth Newspapers chain, is the major daily newspaper serving Ann Arbor and the rest of Washtenaw County. The newspaper ended its 174-year print run in 2009, due to economic difficulties. It was replaced by AnnArbor.com, but returned to a limited print publication under its former name in 2013. Another Ann Arbor-based publication that has ceased production was the Ann Arbor Paper, a free monthly. Ann Arbor has been said to be the first significant city to lose its only daily paper. The Ann Arbor Chronicle, an online newspaper, covered local news, including meetings of the library board, county commission, and DDA until September 3, 2014.


Current publications in the city include the Ann Arbor Journal (A2 Journal), a weekly community newspaper; the Ann Arbor Observer, a free monthly local magazine; the Ann Arbor Independent, a locally owned, independent weekly; and Current, a free entertainment-focused alt-weekly. The Ann Arbor Business Review covers local business in the area. Car and Driver magazine and Automobile Magazine are also based in Ann Arbor. The University of Michigan is served by many student publications, including the independent Michigan Daily student newspaper, which reports on local, state, and regional issues in addition to campus news.


Four major AM radio stations based in or near Ann Arbor are WAAM 1600, a conservative news and talk station; WLBY 1290, a business news and talk station; WDEO 990, Catholic radio; and WTKA 1050, which is primarily a sports station. The city's FM stations include NPR affiliate WUOM 91.7; country station WWWW 102.9; and adult-alternative station WQKL 107.1. Freeform station WCBN-FM 88.3 is a local community radio/college radio station operated by the students of the University of Michigan featuring noncommercial, eclectic music and public-affairs programming. The city is also served by public and commercial radio broadcasters in Ypsilanti, the Lansing/Jackson area, Detroit, Windsor, and Toledo.


WPXD channel 31, an affiliate of the ION Television network, is licensed to the city. WHTV channel 18, a MyNetworkTV-affiliated station for the Lansing market, broadcasts from a transmitter in Lyndon Township, west of Ann Arbor. Community Television Network (CTN) is a city-provided cable television channel with production facilities open to city residents and nonprofit organizations. Detroit and Toledo-area radio and television stations also serve Ann Arbor, and stations from Lansing and Windsor, Ontario, can be heard in parts of the area.


Gothic architecture is a style of architecture that flourished during the high and late medieval period. It evolved from Romanesque architecture and was succeeded by Renaissance architecture. Originating in 12th-century France and lasting into the 16th century, Gothic architecture was known during the period as Opus Francigenum ("French work") with the term Gothic first appearing during the later part of the Renaissance. Its characteristics include the pointed arch, the ribbed vault and the flying buttress. Gothic architecture is most familiar as the architecture of many of the great cathedrals, abbeys and churches of Europe. It is also the architecture of many castles, palaces, town halls, guild halls, universities and to a less prominent extent, private dwellings, such as dorms and rooms.


It is in the great churches and cathedrals and in a number of civic buildings that the Gothic style was expressed most powerfully, its characteristics lending themselves to appeals to the emotions, whether springing from faith or from civic pride. A great number of ecclesiastical buildings remain from this period, of which even the smallest are often structures of architectural distinction while many of the larger churches are considered priceless works of art and are listed with UNESCO as World Heritage Sites. For this reason a study of Gothic architecture is largely a study of cathedrals and churches.


The term "Gothic architecture" originated as a pejorative description. Giorgio Vasari used the term "barbarous German style" in his Lives of the Artists to describe what is now considered the Gothic style, and in the introduction to the Lives he attributes various architectural features to "the Goths" whom he holds responsible for destroying the ancient buildings after they conquered Rome, and erecting new ones in this style. At the time in which Vasari was writing, Italy had experienced a century of building in the Classical architectural vocabulary revived in the Renaissance and seen as evidence of a new Golden Age of learning and refinement.


The greatest number of surviving Gothic buildings are churches. These range from tiny chapels to large cathedrals, and although many have been extended and altered in different styles, a large number remain either substantially intact or sympathetically restored, demonstrating the form, character and decoration of Gothic architecture. The Gothic style is most particularly associated with the great cathedrals of Northern France, the Low Countries, England and Spain, with other fine examples occurring across Europe.


At the end of the 12th century, Europe was divided into a multitude of city states and kingdoms. The area encompassing modern Germany, southern Denmark, the Netherlands, Belgium, Luxembourg, Switzerland, Austria, Slovakia, Czech Republic and much of northern Italy (excluding Venice and Papal State) was nominally part of the Holy Roman Empire, but local rulers exercised considerable autonomy. France, Denmark, Poland, Hungary, Portugal, Scotland, Castile, Aragon, Navarre, Sicily and Cyprus were independent kingdoms, as was the Angevin Empire, whose Plantagenet kings ruled England and large domains in what was to become modern France. Norway came under the influence of England, while the other Scandinavian countries and Poland were influenced by trading contacts with the Hanseatic League. Angevin kings brought the Gothic tradition from France to Southern Italy, while Lusignan kings introduced French Gothic architecture to Cyprus.


Throughout Europe at this time there was a rapid growth in trade and an associated growth in towns. Germany and the Lowlands had large flourishing towns that grew in comparative peace, in trade and competition with each other, or united for mutual weal, as in the Hanseatic League. Civic building was of great importance to these towns as a sign of wealth and pride. England and France remained largely feudal and produced grand domestic architecture for their kings, dukes and bishops, rather than grand town halls for their burghers.


The Catholic Church prevailed across Europe at this time, influencing not only faith but also wealth and power. Bishops were appointed by the feudal lords (kings, dukes and other landowners) and they often ruled as virtual princes over large estates. The early Medieval periods had seen a rapid growth in monasticism, with several different orders being prevalent and spreading their influence widely. Foremost were the Benedictines whose great abbey churches vastly outnumbered any others in France and England. A part of their influence was that towns developed around them and they became centers of culture, learning and commerce. The Cluniac and Cistercian Orders were prevalent in France, the great monastery at Cluny having established a formula for a well planned monastic site which was then to influence all subsequent monastic building for many centuries.


From the 10th to the 13th century, Romanesque architecture had become a pan-European style and manner of construction, affecting buildings in countries as far apart as Ireland, Croatia, Sweden and Sicily. The same wide geographic area was then affected by the development of Gothic architecture, but the acceptance of the Gothic style and methods of construction differed from place to place, as did the expressions of Gothic taste. The proximity of some regions meant that modern country borders do not define divisions of style. On the other hand, some regions such as England and Spain produced defining characteristics rarely seen elsewhere, except where they have been carried by itinerant craftsmen, or the transfer of bishops. Regional differences that are apparent in the great abbey churches and cathedrals of the Romanesque period often become even more apparent in the Gothic.


In Northern Germany, Netherlands, northern Poland, Denmark, and the Baltic countries local building stone was unavailable but there was a strong tradition of building in brick. The resultant style, Brick Gothic, is called "Backsteingotik" in Germany and Scandinavia and is associated with the Hanseatic League. In Italy, stone was used for fortifications, but brick was preferred for other buildings. Because of the extensive and varied deposits of marble, many buildings were faced in marble, or were left with undecorated façade so that this might be achieved at a later date.


By the 12th century, Romanesque architecture (termed Norman architecture in England because of its association with the Norman invasion), was established throughout Europe and provided the basic architectural forms and units that were to remain in evolution throughout the Medieval period. The important categories of building: the cathedral church, the parish church, the monastery, the castle, the palace, the great hall, the gatehouse, the civic building, had been established in the Romanesque period.


It was principally the widespread introduction of a single feature, the pointed arch, which was to bring about the change that separates Gothic from Romanesque. The technological change permitted a stylistic change which broke the tradition of massive masonry and solid walls penetrated by small openings, replacing it with a style where light appears to triumph over substance. With its use came the development of many other architectural devices, previously put to the test in scattered buildings and then called into service to meet the structural, aesthetic and ideological needs of the new style. These include the flying buttresses, pinnacles and traceried windows which typify Gothic ecclesiastical architecture. But while pointed arch is so strongly associated with the Gothic style, it was first used in Western architecture in buildings that were in other ways clearly Romanesque, notably Durham Cathedral in the north of England, Monreale Cathedral and Cathedral of Cefalù in Sicily, Autun Cathedral in France.


The pointed arch, one of the defining attributes of Gothic, was earlier incorporated into Islamic architecture following the Islamic conquests of Roman Syria and the Sassanid Empire in the Seventh Century. The pointed arch and its precursors had been employed in Late Roman and Sassanian architecture; within the Roman context, evidenced in early church building in Syria and occasional secular structures, like the Roman Karamagara Bridge; in Sassanid architecture, in the parabolic and pointed arches employed in palace and sacred construction.


Increasing military and cultural contacts with the Muslim world, including the Norman conquest of Islamic Sicily in 1090, the Crusades, beginning 1096, and the Islamic presence in Spain, may have influenced Medieval Europe's adoption of the pointed arch, although this hypothesis remains controversial. Certainly, in those parts of the Western Mediterranean subject to Islamic control or influence, rich regional variants arose, fusing Romanesque and later Gothic traditions with Islamic decorative forms, as seen, for example, in Monreale and Cefalù Cathedrals, the Alcázar of Seville, and Teruel Cathedral.


The characteristic forms that were to define Gothic architecture grew out of Romanesque architecture and developed at several different geographic locations, as the result of different influences and structural requirements. While barrel vaults and groin vaults are typical of Romanesque architecture, ribbed vaults were used in the naves of two Romanesque churches in Caen, Abbey of Saint-Étienne and Abbaye aux Dames in 1120. Another early example is the nave and apse area of the Cathedral of Cefalù in 1131. The ribbed vault over the north transept at Durham Cathedral in England, built from 1128 to 1133, is probably earlier still and was the first time pointed arches were used in a high vault.


The Basilica of Saint Denis is generally cited as the first truly Gothic building, however the distinction is best reserved for the choir, of which the ambulatory remains intact. Noyon Cathedral, also in France, saw the earliest completion of a rebuilding of an entire cathedral in the new style from 1150 to 1231. While using all those features that came to be known as Gothic, including pointed arches, flying buttresses and ribbed vaulting, the builders continued to employ many of the features and much of the character of Romanesque architecture including round-headed arch throughout the building, varying the shape to pointed where it was functionally practical to do so.


At the Abbey Saint-Denis, Noyon Cathedral, Notre Dame de Paris and at the eastern end of Canterbury Cathedral in England, simple cylindrical columns predominate over the Gothic forms of clustered columns and shafted piers. Wells Cathedral in England, commenced at the eastern end in 1175, was the first building in which the designer broke free from Romanesque forms. The architect entirely dispensed with the round arch in favour of the pointed arch and with cylindrical columns in favour of piers composed of clusters of shafts which lead into the mouldings of the arches. The transepts and nave were continued by Adam Locke in the same style and completed in about 1230. The character of the building is entirely Gothic. Wells Cathedral is thus considered the first truly Gothic cathedral.


Suger, friend and confidant of the French Kings, Louis VI and Louis VII, decided in about 1137, to rebuild the great Church of Saint-Denis, attached to an abbey which was also a royal residence. He began with the West Front, reconstructing the original Carolingian façade with its single door. He designed the façade of Saint-Denis to be an echo of the Roman Arch of Constantine with its three-part division and three large portals to ease the problem of congestion. The rose window is the earliest-known example above the West portal in France. The façade combines both round arches and pointed arches of the Gothic style.


At the completion of the west front in 1140, Abbot Suger moved on to the reconstruction of the eastern end, leaving the Carolingian nave in use. He designed a choir that would be suffused with light. To achieve his aims, his masons drew on the several new features which evolved or had been introduced to Romanesque architecture, the pointed arch, the ribbed vault, the ambulatory with radiating chapels, the clustered columns supporting ribs springing in different directions and the flying buttresses which enabled the insertion of large clerestory windows.


While many secular buildings exist from the Late Middle Ages, it is in the buildings of cathedrals and great churches that Gothic architecture displays its pertinent structures and characteristics to the fullest advantage. A Gothic cathedral or abbey was, prior to the 20th century, generally the landmark building in its town, rising high above all the domestic structures and often surmounted by one or more towers and pinnacles and perhaps tall spires. These cathedrals were the skyscrapers of that day and would have been the largest buildings by far that Europeans would ever have seen. It is in the architecture of these Gothic churches that a unique combination of existing technologies established the emergence of a new building style. Those technologies were the ogival or pointed arch, the ribbed vault, and the buttress.


The eastern arm shows considerable diversity. In England it is generally long and may have two distinct sections, both choir and presbytery. It is often square ended or has a projecting Lady Chapel, dedicated to the Virgin Mary. In France the eastern end is often polygonal and surrounded by a walkway called an ambulatory and sometimes a ring of chapels called a "chevet". While German churches are often similar to those of France, in Italy, the eastern projection beyond the transept is usually just a shallow apsidal chapel containing the sanctuary, as at Florence Cathedral.


Contrary to the diffusionist theory, it appears that there was simultaneously a structural evolution towards the pointed arch, for the purpose of vaulting spaces of irregular plan, or to bring transverse vaults to the same height as diagonal vaults. This latter occurs at Durham Cathedral in the nave aisles in 1093. Pointed arches also occur extensively in Romanesque decorative blind arcading, where semi-circular arches overlap each other in a simple decorative pattern, and the points are accidental to the design.


The Gothic vault, unlike the semi-circular vault of Roman and Romanesque buildings, can be used to roof rectangular and irregularly shaped plans such as trapezoids. The other structural advantage is that the pointed arch channels the weight onto the bearing piers or columns at a steep angle. This enabled architects to raise vaults much higher than was possible in Romanesque architecture. While, structurally, use of the pointed arch gave a greater flexibility to architectural form, it also gave Gothic architecture a very different and more vertical visual character than Romanesque.


Externally, towers and spires are characteristic of Gothic churches both great and small, the number and positioning being one of the greatest variables in Gothic architecture. In Italy, the tower, if present, is almost always detached from the building, as at Florence Cathedral, and is often from an earlier structure. In France and Spain, two towers on the front is the norm. In England, Germany and Scandinavia this is often the arrangement, but an English cathedral may also be surmounted by an enormous tower at the crossing. Smaller churches usually have just one tower, but this may also be the case at larger buildings, such as Salisbury Cathedral or Ulm Minster, which has the tallest spire in the world, slightly exceeding that of Lincoln Cathedral, the tallest which was actually completed during the medieval period, at 160 metres (520 ft).


On the exterior, the verticality is emphasised in a major way by the towers and spires and in a lesser way by strongly projecting vertical buttresses, by narrow half-columns called attached shafts which often pass through several storeys of the building, by long narrow windows, vertical mouldings around doors and figurative sculpture which emphasises the vertical and is often attenuated. The roofline, gable ends, buttresses and other parts of the building are often terminated by small pinnacles, Milan Cathedral being an extreme example in the use of this form of decoration.


On the interior of the building attached shafts often sweep unbroken from floor to ceiling and meet the ribs of the vault, like a tall tree spreading into branches. The verticals are generally repeated in the treatment of the windows and wall surfaces. In many Gothic churches, particularly in France, and in the Perpendicular period of English Gothic architecture, the treatment of vertical elements in gallery and window tracery creates a strongly unifying feature that counteracts the horizontal divisions of the interior structure.


Expansive interior light has been a feature of Gothic cathedrals since the first structure was opened. The metaphysics of light in the Middle Ages led to clerical belief in its divinity and the importance of its display in holy settings. Much of this belief was based on the writings of Pseudo-Dionysius, a sixth-century mystic whose book, The Celestial Hierarchy, was popular among monks in France. Pseudo-Dionysius held that all light, even light reflected from metals or streamed through windows, was divine. To promote such faith, the abbot in charge of the Saint-Denis church on the north edge of Paris, the Abbot Suger, encouraged architects remodeling the building to make the interior as bright as possible.


Above the main portal there is generally a large window, like that at York Minster, or a group of windows such as those at Ripon Cathedral. In France there is generally a rose window like that at Reims Cathedral. Rose windows are also often found in the façades of churches of Spain and Italy, but are rarer elsewhere and are not found on the façades of any English Cathedrals. The gable is usually richly decorated with arcading or sculpture or, in the case of Italy, may be decorated with the rest of the façade, with polychrome marble and mosaic, as at Orvieto Cathedral.


The distinctive characteristic of French cathedrals, and those in Germany and Belgium that were strongly influenced by them, is their height and their impression of verticality. Each French cathedral tends to be stylistically unified in appearance when compared with an English cathedral where there is great diversity in almost every building. They are compact, with slight or no projection of the transepts and subsidiary chapels. The west fronts are highly consistent, having three portals surmounted by a rose window, and two large towers. Sometimes there are additional towers on the transept ends. The east end is polygonal with ambulatory and sometimes a chevette of radiating chapels. In the south of France, many of the major churches are without transepts and some are without aisles.


The distinctive characteristic of English cathedrals is their extreme length, and their internal emphasis upon the horizontal, which may be emphasised visually as much or more than the vertical lines. Each English cathedral (with the exception of Salisbury) has an extraordinary degree of stylistic diversity, when compared with most French, German and Italian cathedrals. It is not unusual for every part of the building to have been built in a different century and in a different style, with no attempt at creating a stylistic unity. Unlike French cathedrals, English cathedrals sprawl across their sites, with double transepts projecting strongly and Lady Chapels tacked on at a later date, such as at Westminster Abbey. In the west front, the doors are not as significant as in France, the usual congregational entrance being through a side porch. The West window is very large and never a rose, which are reserved for the transept gables. The west front may have two towers like a French Cathedral, or none. There is nearly always a tower at the crossing and it may be very large and surmounted by a spire. The distinctive English east end is square, but it may take a completely different form. Both internally and externally, the stonework is often richly decorated with carvings, particularly the capitals.


Romanesque architecture in Germany, Poland, the Czech Lands and Austria is characterised by its massive and modular nature. This is expressed in the Gothic architecture of Central Europe in the huge size of the towers and spires, often projected, but not always completed. The west front generally follows the French formula, but the towers are very much taller and, if complete, are surmounted by enormous openwork spires that are a regional feature. Because of the size of the towers, the section of the façade between them may appear narrow and compressed. The eastern end follows the French form. The distinctive character of the interior of German Gothic cathedrals is their breadth and openness. This is the case even when, as at Cologne, they have been modelled upon a French cathedral. German cathedrals, like the French, tend not to have strongly projecting transepts. There are also many hall churches (Hallenkirchen) without clerestory windows.


The distinctive characteristic of Gothic cathedrals of the Iberian Peninsula is their spatial complexity, with many areas of different shapes leading from each other. They are comparatively wide, and often have very tall arcades surmounted by low clerestories, giving a similar spacious appearance to the 'Hallenkirche of Germany, as at the Church of the Batalha Monastery in Portugal. Many of the cathedrals are completely surrounded by chapels. Like English cathedrals, each is often stylistically diverse. This expresses itself both in the addition of chapels and in the application of decorative details drawn from different sources. Among the influences on both decoration and form are Islamic architecture and, towards the end of the period, Renaissance details combined with the Gothic in a distinctive manner. The West front, as at Leon Cathedral, typically resembles a French west front, but wider in proportion to height and often with greater diversity of detail and a combination of intricate ornament with broad plain surfaces. At Burgos Cathedral there are spires of German style. The roofline often has pierced parapets with comparatively few pinnacles. There are often towers and domes of a great variety of shapes and structural invention rising above the roof.


The distinctive characteristic of Italian Gothic is the use of polychrome decoration, both externally as marble veneer on the brick façade and also internally where the arches are often made of alternating black and white segments, and where the columns may be painted red, the walls decorated with frescoes and the apse with mosaic. The plan is usually regular and symmetrical, Italian cathedrals have few and widely spaced columns. The proportions are generally mathematically equilibrated, based on the square and the concept of "armonìa", and except in Venice where they loved flamboyant arches, the arches are almost always equilateral. Colours and moldings define the architectural units rather than blending them. Italian cathedral façades are often polychrome and may include mosaics in the lunettes over the doors. The façades have projecting open porches and occular or wheel windows rather than roses, and do not usually have a tower. The crossing is usually surmounted by a dome. There is often a free-standing tower and baptistry. The eastern end usually has an apse of comparatively low projection. The windows are not as large as in northern Europe and, although stained glass windows are often found, the favourite narrative medium for the interior is the fresco.


The Palais des Papes in Avignon is the best complete large royal palace, alongside the Royal palace of Olite, built during the 13th and 14th centuries for the kings of Navarre. The Malbork Castle built for the master of the Teutonic order is an example of Brick Gothic architecture. Partial survivals of former royal residences include the Doge's Palace of Venice, the Palau de la Generalitat in Barcelona, built in the 15th century for the kings of Aragon, or the famous Conciergerie, former palace of the kings of France, in Paris.


Secular Gothic architecture can also be found in a number of public buildings such as town halls, universities, markets or hospitals. The Gdańsk, Wrocław and Stralsund town halls are remarkable examples of northern Brick Gothic built in the late 14th centuries. The Belfry of Bruges or Brussels Town Hall, built during the 15th century, are associated to the increasing wealth and power of the bourgeoisie in the late Middle Ages; by the 15th century, the traders of the trade cities of Burgundy had acquired such wealth and influence that they could afford to express their power by funding lavishly decorated buildings of vast proportions. This kind of expressions of secular and economic power are also found in other late mediaeval commercial cities, including the Llotja de la Seda of Valencia, Spain, a purpose built silk exchange dating from the 15th century, in the partial remains of Westminster Hall in the Houses of Parliament in London, or the Palazzo Pubblico in Siena, Italy, a 13th-century town hall built to host the offices of the then prosperous republic of Siena. Other Italian cities such as Florence (Palazzo Vecchio), Mantua or Venice also host remarkable examples of secular public architecture.


By the late Middle Ages university towns had grown in wealth and importance as well, and this was reflected in the buildings of some of Europe's ancient universities. Particularly remarkable examples still standing nowadays include the Collegio di Spagna in the University of Bologna, built during the 14th and 15th centuries; the Collegium Carolinum of the University of Prague in Bohemia; the Escuelas mayores of the University of Salamanca in Spain; the chapel of King's College, Cambridge; or the Collegium Maius of the Jagiellonian University in Kraków, Poland.


Other cities with a concentration of secular Gothic include Bruges and Siena. Most surviving small secular buildings are relatively plain and straightforward; most windows are flat-topped with mullions, with pointed arches and vaulted ceilings often only found at a few focal points. The country-houses of the nobility were slow to abandon the appearance of being a castle, even in parts of Europe, like England, where defence had ceased to be a real concern. The living and working parts of many monastic buildings survive, for example at Mont Saint-Michel.


In 1663 at the Archbishop of Canterbury's residence, Lambeth Palace, a Gothic hammerbeam roof was built to replace that destroyed when the building was sacked during the English Civil War. Also in the late 17th century, some discrete Gothic details appeared on new construction at Oxford University and Cambridge University, notably on Tom Tower at Christ Church, Oxford, by Christopher Wren. It is not easy to decide whether these instances were Gothic survival or early appearances of Gothic revival.


In England, partly in response to a philosophy propounded by the Oxford Movement and others associated with the emerging revival of 'high church' or Anglo-Catholic ideas during the second quarter of the 19th century, neo-Gothic began to become promoted by influential establishment figures as the preferred style for ecclesiastical, civic and institutional architecture. The appeal of this Gothic revival (which after 1837, in Britain, is sometimes termed Victorian Gothic), gradually widened to encompass "low church" as well as "high church" clients. This period of more universal appeal, spanning 1855–1885, is known in Britain as High Victorian Gothic.


The Houses of Parliament in London by Sir Charles Barry with interiors by a major exponent of the early Gothic Revival, Augustus Welby Pugin, is an example of the Gothic revival style from its earlier period in the second quarter of the 19th century. Examples from the High Victorian Gothic period include George Gilbert Scott's design for the Albert Memorial in London, and William Butterfield's chapel at Keble College, Oxford. From the second half of the 19th century onwards it became more common in Britain for neo-Gothic to be used in the design of non-ecclesiastical and non-governmental buildings types. Gothic details even began to appear in working-class housing schemes subsidised by philanthropy, though given the expense, less frequently than in the design of upper and middle-class housing.


In France, simultaneously, the towering figure of the Gothic Revival was Eugène Viollet-le-Duc, who outdid historical Gothic constructions to create a Gothic as it ought to have been, notably at the fortified city of Carcassonne in the south of France and in some richly fortified keeps for industrial magnates. Viollet-le-Duc compiled and coordinated an Encyclopédie médiévale that was a rich repertory his contemporaries mined for architectural details. He effected vigorous restoration of crumbling detail of French cathedrals, including the Abbey of Saint-Denis and famously at Notre Dame de Paris, where many of whose most "Gothic" gargoyles are Viollet-le-Duc's. He taught a generation of reform-Gothic designers and showed how to apply Gothic style to modern structural materials, especially cast iron.


The movement was pioneered by Georges Braque and Pablo Picasso, joined by Jean Metzinger, Albert Gleizes, Robert Delaunay, Henri Le Fauconnier, Fernand Léger and Juan Gris. A primary influence that led to Cubism was the representation of three-dimensional form in the late works of Paul Cézanne. A retrospective of Cézanne's paintings had been held at the Salon d'Automne of 1904, current works were displayed at the 1905 and 1906 Salon d'Automne, followed by two commemorative retrospectives after his death in 1907.


In France, offshoots of Cubism developed, including Orphism, Abstract art and later Purism. In other countries Futurism, Suprematism, Dada, Constructivism and De Stijl developed in response to Cubism. Early Futurist paintings hold in common with Cubism the fusing of the past and the present, the representation of different views of the subject pictured at the same time, also called multiple perspective, simultaneity or multiplicity, while Constructivism was influenced by Picasso's technique of constructing sculpture from separate elements. Other common threads between these disparate movements include the faceting or simplification of geometric forms, and the association of mechanization and modern life.


Cubism began between 1907 and 1911. Pablo Picasso's 1907 painting Les Demoiselles d'Avignon has often been considered a proto-Cubist work. Georges Braque's 1908 Houses at L’Estaque (and related works) prompted the critic Louis Vauxcelles to refer to bizarreries cubiques (cubic oddities). Gertrude Stein referred to landscapes made by Picasso in 1909, such as Reservoir at Horta de Ebro, as the first Cubist paintings. The first organized group exhibition by Cubists took place at the Salon des Indépendants in Paris during the spring of 1911 in a room called 'Salle 41'; it included works by Jean Metzinger, Albert Gleizes, Fernand Léger, Robert Delaunay and Henri Le Fauconnier, yet no works by Picasso or Braque were exhibited.


Historians have divided the history of Cubism into phases. In one scheme, the first phase of Cubism, known as Analytic Cubism, a phrase coined by Juan Gris a posteriori, was both radical and influential as a short but highly significant art movement between 1910 and 1912 in France. A second phase, Synthetic Cubism, remained vital until around 1919, when the Surrealist movement gained popularity. English art historian Douglas Cooper proposed another scheme, describing three phases of Cubism in his book, The Cubist Epoch. According to Cooper there was "Early Cubism", (from 1906 to 1908) when the movement was initially developed in the studios of Picasso and Braque; the second phase being called "High Cubism", (from 1909 to 1914) during which time Juan Gris emerged as an important exponent (after 1911); and finally Cooper referred to "Late Cubism" (from 1914 to 1921) as the last phase of Cubism as a radical avant-garde movement. Douglas Cooper's restrictive use of these terms to distinguish the work of Braque, Picasso, Gris (from 1911) and Léger (to a lesser extent) implied an intentional value judgement.


The assertion that the Cubist depiction of space, mass, time, and volume supports (rather than contradicts) the flatness of the canvas was made by Daniel-Henry Kahnweiler as early as 1920, but it was subject to criticism in the 1950s and 1960s, especially by Clement Greenberg. Contemporary views of Cubism are complex, formed to some extent in response to the "Salle 41" Cubists, whose methods were too distinct from those of Picasso and Braque to be considered merely secondary to them. Alternative interpretations of Cubism have therefore developed. Wider views of Cubism include artists who were later associated with the "Salle 41" artists, e.g., Francis Picabia; the brothers Jacques Villon, Raymond Duchamp-Villon and Marcel Duchamp, who beginning in late 1911 formed the core of the Section d'Or (or the Puteaux Group); the sculptors Alexander Archipenko, Joseph Csaky and Ossip Zadkine as well as Jacques Lipchitz and Henri Laurens; and painters such as Louis Marcoussis, Roger de La Fresnaye, František Kupka, Diego Rivera, Léopold Survage, Auguste Herbin, André Lhote, Gino Severini (after 1916), María Blanchard (after 1916) and Georges Valmier (after 1918). More fundamentally, Christopher Green argues that Douglas Cooper's terms were "later undermined by interpretations of the work of Picasso, Braque, Gris and Léger that stress iconographic and ideological questions rather than methods of representation."


During the late 19th and early 20th centuries, Europeans were discovering African, Polynesian, Micronesian and Native American art. Artists such as Paul Gauguin, Henri Matisse, and Pablo Picasso were intrigued and inspired by the stark power and simplicity of styles of those foreign cultures. Around 1906, Picasso met Matisse through Gertrude Stein, at a time when both artists had recently acquired an interest in primitivism, Iberian sculpture, African art and African tribal masks. They became friendly rivals and competed with each other throughout their careers, perhaps leading to Picasso entering a new period in his work by 1907, marked by the influence of Greek, Iberian and African art. Picasso's paintings of 1907 have been characterized as Protocubism, as notably seen in Les Demoiselles d'Avignon, the antecedent of Cubism.


The art historian Douglas Cooper states that Paul Gauguin and Paul Cézanne "were particularly influential to the formation of Cubism and especially important to the paintings of Picasso during 1906 and 1907". Cooper goes on to say: "The Demoiselles is generally referred to as the first Cubist picture. This is an exaggeration, for although it was a major first step towards Cubism it is not yet Cubist. The disruptive, expressionist element in it is even contrary to the spirit of Cubism, which looked at the world in a detached, realistic spirit. Nevertheless, the Demoiselles is the logical picture to take as the starting point for Cubism, because it marks the birth of a new pictorial idiom, because in it Picasso violently overturned established conventions and because all that followed grew out of it."


The most serious objection to regarding the Demoiselles as the origin of Cubism, with its evident influence of primitive art, is that "such deductions are unhistorical", wrote the art historian Daniel Robbins. This familiar explanation "fails to give adequate consideration to the complexities of a flourishing art that existed just before and during the period when Picasso's new painting developed." Between 1905 and 1908, a conscious search for a new style caused rapid changes in art across France, Germany, Holland, Italy, and Russia. The Impressionists had used a double point of view, and both Les Nabis and the Symbolists (who also admired Cézanne) flattened the picture plane, reducing their subjects to simple geometric forms. Neo-Impressionist structure and subject matter, most notably to be seen in the works of Georges Seurat (e.g., Parade de Cirque, Le Chahut and Le Cirque), was another important influence. There were also parallels in the development of literature and social thought.


In addition to Seurat, the roots of cubism are to be found in the two distinct tendencies of Cézanne's later work: first his breaking of the painted surface into small multifaceted areas of paint, thereby emphasizing the plural viewpoint given by binocular vision, and second his interest in the simplification of natural forms into cylinders, spheres, and cones. However, the cubists explored this concept further than Cézanne. They represented all the surfaces of depicted objects in a single picture plane, as if the objects had all their faces visible at the same time. This new kind of depiction revolutionized the way objects could be visualized in painting and art.


The historical study of Cubism began in the late 1920s, drawing at first from sources of limited data, namely the opinions of Guillaume Apollinaire. It came to rely heavily on Daniel-Henry Kahnweiler's book Der Weg zum Kubismus (published in 1920), which centered on the developments of Picasso, Braque, Léger, and Gris. The terms "analytical" and "synthetic" which subsequently emerged have been widely accepted since the mid-1930s. Both terms are historical impositions that occurred after the facts they identify. Neither phase was designated as such at the time corresponding works were created. "If Kahnweiler considers Cubism as Picasso and Braque," wrote Daniel Robbins, "our only fault is in subjecting other Cubists' works to the rigors of that limited definition."


The traditional interpretation of "Cubism", formulated post facto as a means of understanding the works of Braque and Picasso, has affected our appreciation of other twentieth-century artists. It is difficult to apply to painters such as Jean Metzinger, Albert Gleizes, Robert Delaunay and Henri Le Fauconnier, whose fundamental differences from traditional Cubism compelled Kahnweiler to question their right to be called Cubists at all. According to Daniel Robbins, "To suggest that merely because these artists developed differently or varied from the traditional pattern they deserved to be relegated to a secondary or satellite role in Cubism is a profound mistake."


The term Cubism did not come into general usage until 1911, mainly with reference to Metzinger, Gleizes, Delaunay, and Léger. In 1911, the poet and critic Guillaume Apollinaire accepted the term on behalf of a group of artists invited to exhibit at the Brussels Indépendants. The following year, in preparation for the Salon de la Section d'Or, Metzinger and Gleizes wrote and published Du "Cubisme" in an effort to dispel the confusion raging around the word, and as a major defence of Cubism (which had caused a public scandal following the 1911 Salon des Indépendants and the 1912 Salon d'Automne in Paris). Clarifying their aims as artists, this work was the first theoretical treatise on Cubism and it still remains the clearest and most intelligible. The result, not solely a collaboration between its two authors, reflected discussions by the circle of artists who met in Puteaux and Courbevoie. It mirrored the attitudes of the "artists of Passy", which included Picabia and the Duchamp brothers, to whom sections of it were read prior to publication. The concept developed in Du "Cubisme" of observing a subject from different points in space and time simultaneously, i.e., the act of moving around an object to seize it from several successive angles fused into a single image (multiple viewpoints, mobile perspective, simultaneity or multiplicity), is a generally recognized device used by the Cubists.


There was a distinct difference between Kahnweiler’s Cubists and the Salon Cubists. Prior to 1914, Picasso, Braque, Gris and Léger (to a lesser extent) gained the support of a single committed art dealer in Paris, Daniel-Henry Kahnweiler, who guaranteed them an annual income for the exclusive right to buy their works. Kahnweiler sold only to a small circle of connoisseurs. His support gave his artists the freedom to experiment in relative privacy. Picasso worked in Montmartre until 1912, while Braque and Gris remained there until after the First World War. Léger was based in Montparnasse.


In contrast, the Salon Cubists built their reputation primarily by exhibiting regularly at the Salon d'Automne and the Salon des Indépendants, both major non-academic Salons in Paris. They were inevitably more aware of public response and the need to communicate. Already in 1910 a group began to form which included Metzinger, Gleizes, Delaunay and Léger. They met regularly at Henri le Fauconnier's studio near the Boulevard de Montparnasse. These soirées often included writers such as Guillaume Apollinaire and André Salmon. Together with other young artists, the group wanted to emphasise a research into form, in opposition to the Neo-Impressionist emphasis on color.


At the Salon d'Automne of the same year, in addition to the Indépendants group of Salle 41, were exhibited works by André Lhote, Marcel Duchamp, Jacques Villon, Roger de La Fresnaye, André Dunoyer de Segonzac and František Kupka. The exhibition was reviewed in the October 8, 1911 issue of The New York Times. This article was published a year after Gelett Burgess' The Wild Men of Paris, and two years prior to the Armory Show, which introduced astonished Americans, accustomed to realistic art, to the experimental styles of the European avant garde, including Fauvism, Cubism, and Futurism. The 1911 New York Times article portrayed works by Picasso, Matisse, Derain, Metzinger and others dated before 1909; not exhibited at the 1911 Salon. The article was titled The "Cubists" Dominate Paris' Fall Salon and subtitled Eccentric School of Painting Increases Its Vogue in the Current Art Exhibition - What Its Followers Attempt to Do.


The subsequent 1912 Salon des Indépendants was marked by the presentation of Marcel Duchamp's Nude Descending a Staircase, No. 2, which itself caused a scandal, even amongst the Cubists. It was in fact rejected by the hanging committee, which included his brothers and other Cubists. Although the work was shown in the Salon de la Section d'Or in October 1912 and the 1913 Armory Show in New York, Duchamp never forgave his brothers and former colleagues for censoring his work. Juan Gris, a new addition to the Salon scene, exhibited his Portrait of Picasso (Art Institute of Chicago), while Metzinger's two showings included La Femme au Cheval (Woman with a horse) 1911-1912 (National Gallery of Denmark). Delaunay's monumental La Ville de Paris (Musée d'art moderne de la Ville de Paris) and Léger's La Noce, The Wedding (Musée National d'Art Moderne, Paris) were also exhibited.


The Cubist contribution to the 1912 Salon d'Automne created scandal regarding the use of government owned buildings, such as the Grand Palais, to exhibit such artwork. The indignation of the politician Jean Pierre Philippe Lampué made the front page of Le Journal, 5 October 1912. The controversy spread to the Municipal Council of Paris, leading to a debate in the Chambre des Députés about the use of public funds to provide the venue for such art. The Cubists were defended by the Socialist deputy, Marcel Sembat.


It was against this background of public anger that Jean Metzinger and Albert Gleizes wrote Du "Cubisme" (published by Eugène Figuière in 1912, translated to English and Russian in 1913). Among the works exhibited were Le Fauconnier's vast composition Les Montagnards attaqués par des ours (Mountaineers Attacked by Bears) now at Rhode Island School of Design Museum, Joseph Csaky's Deux Femme, Two Women (a sculpture now lost), in addition to the highly abstract paintings by Kupka, Amorpha (The National Gallery, Prague), and Picabia, La Source, The Spring (Museum of Modern Art, New York).


The most extreme forms of Cubism were not those practiced by Picasso and Braque, who resisted total abstraction. Other Cubists, by contrast, especially František Kupka, and those considered Orphists by Apollinaire (Delaunay, Léger, Picabia and Duchamp), accepted abstraction by removing visible subject matter entirely. Kupka’s two entries at the 1912 Salon d'Automne, Amorpha-Fugue à deux couleurs and Amorpha chromatique chaude, were highly abstract (or nonrepresentational) and metaphysical in orientation. Both Duchamp in 1912 and Picabia from 1912 to 1914 developed an expressive and allusive abstraction dedicated to complex emotional and sexual themes. Beginning in 1912 Delaunay painted a series of paintings entitled Simultaneous Windows, followed by a series entitled Formes Circulaires, in which he combined planar structures with bright prismatic hues; based on the optical characteristics of juxtaposed colors his departure from reality in the depiction of imagery was quasi-complete. In 1913–14 Léger produced a series entitled Contrasts of Forms, giving a similar stress to color, line and form. His Cubism, despite its abstract qualities, was associated with themes of mechanization and modern life. Apollinaire supported these early developments of abstract Cubism in Les Peintres cubistes (1913), writing of a new "pure" painting in which the subject was vacated. But in spite of his use of the term Orphism these works were so different that they defy attempts to place them in a single category.


Also labeled an Orphist by Apollinaire, Marcel Duchamp was responsible for another extreme development inspired by Cubism. The ready-made arose from a joint consideration that the work itself is considered an object (just as a painting), and that it uses the material detritus of the world (as collage and papier collé in the Cubist construction and Assemblage). The next logical step, for Duchamp, was to present an ordinary object as a self-sufficient work of art representing only itself. In 1913 he attached a bicycle wheel to a kitchen stool and in 1914 selected a bottle-drying rack as a sculpture in its own right.


The Section d'Or, also known as Groupe de Puteaux, founded by some of the most conspicuous Cubists, was a collective of painters, sculptors and critics associated with Cubism and Orphism, active from 1911 through about 1914, coming to prominence in the wake of their controversial showing at the 1911 Salon des Indépendants. The Salon de la Section d'Or at the Galerie La Boétie in Paris, October 1912, was arguably the most important pre-World War I Cubist exhibition; exposing Cubism to a wide audience. Over 200 works were displayed, and the fact that many of the artists showed artworks representative of their development from 1909 to 1912 gave the exhibition the allure of a Cubist retrospective.


The fact that the 1912 exhibition had been curated to show the successive stages through which Cubism had transited, and that Du "Cubisme" had been published for the occasion, indicates the artists' intention of making their work comprehensible to a wide audience (art critics, art collectors, art dealers and the general public). Undoubtedly, due to the great success of the exhibition, Cubism became recognized as a tendency, genre or style in art with a specific common philosophy or goal: a new avant-garde movement.


The Cubism of Picasso, Braque and Gris had more than a technical or formal significance, and the distinct attitudes and intentions of the Salon Cubists produced different kinds of Cubism, rather than a derivative of their work. "It is by no means clear, in any case," wrote Christopher Green, "to what extent these other Cubists depended on Picasso and Braque for their development of such techniques as faceting, 'passage' and multiple perspective; they could well have arrived at such practices with little knowledge of 'true' Cubism in its early stages, guided above all by their own understanding of Cézanne." The works exhibited by these Cubists at the 1911 and 1912 Salons extended beyond the conventional Cézanne-like subjects—the posed model, still-life and landscape—favored by Picasso and Braque to include large-scale modern-life subjects. Aimed at a large public, these works stressed the use of multiple perspective and complex planar faceting for expressive effect while preserving the eloquence of subjects endowed with literary and philosophical connotations.


In Du "Cubisme" Metzinger and Gleizes explicitly related the sense of time to multiple perspective, giving symbolic expression to the notion of ‘duration’ proposed by the philosopher Henri Bergson according to which life is subjectively experienced as a continuum, with the past flowing into the present and the present merging into the future. The Salon Cubists used the faceted treatment of solid and space and effects of multiple viewpoints to convey a physical and psychological sense of the fluidity of consciousness, blurring the distinctions between past, present and future. One of the major theoretical innovations made by the Salon Cubists, independently of Picasso and Braque, was that of simultaneity, drawing to greater or lesser extent on theories of Henri Poincaré, Ernst Mach, Charles Henry, Maurice Princet, and Henri Bergson. With simultaneity, the concept of separate spatial and temporal dimensions was comprehensively challenged. Linear perspective developed during the Renaissance was vacated. The subject matter was no longer considered from a specific point of view at a moment in time, but built following a selection of successive viewpoints, i.e., as if viewed simultaneously from numerous angles (and in multiple dimensions) with the eye free to roam from one to the other.


This technique of representing simultaneity, multiple viewpoints (or relative motion) is pushed to a high degree of complexity in Gleizes' monumental Le Dépiquage des Moissons (Harvest Threshing), exhibited at the 1912 Salon de la Section d'Or, Le Fauconnier’s Abundance shown at the Indépendants of 1911, and Delaunay's City of Paris, shown at the Indépendants in 1912. These ambitious works are some of the largest paintings in the history of Cubism. Léger’s The Wedding, also shown at the Salon des Indépendants in 1912, gave form to the notion of simultaneity by presenting different motifs as occurring within a single temporal frame, where responses to the past and present interpenetrate with collective force. The conjunction of such subject matter with simultaneity aligns Salon Cubism with early Futurist paintings by Umberto Boccioni, Gino Severini and Carlo Carrà; themselves made in response to early Cubism.


Cubism and modern European art was introduced into the United States at the now legendary 1913 Armory Show in New York City, which then traveled to Chicago and Boston. In the Armory show Pablo Picasso exhibited La Femme au pot de moutarde (1910), the sculpture Head of a Woman (Fernande) (1909–10), Les Arbres (1907) amongst other cubist works. Jacques Villon exhibited seven important and large drypoints, his brother Marcel Duchamp shocked the American public with his painting Nude Descending a Staircase, No. 2 (1912). Francis Picabia exhibited his abstractions La Danse à la source and La Procession, Seville (both of 1912). Albert Gleizes exhibited La Femme aux phlox (1910) and L'Homme au balcon (1912), two highly stylized and faceted cubist works. Georges Braque, Fernand Léger, Raymond Duchamp-Villon, Roger de La Fresnaye and Alexander Archipenko also contributed examples of their cubist works.


Cubist sculpture developed in parallel to Cubist painting. During the autumn of 1909 Picasso sculpted Head of a Woman (Fernande) with positive features depicted by negative space and vice versa. According to Douglas Cooper: "The first true Cubist sculpture was Picasso's impressive Woman's Head, modeled in 1909–10, a counterpart in three dimensions to many similar analytical and faceted heads in his paintings at the time." These positive/negative reversals were ambitiously exploited by Alexander Archipenko in 1912–13, for example in Woman Walking. Joseph Csaky, after Archipenko, was the first sculptor in Paris to join the Cubists, with whom he exhibited from 1911 onwards. They were followed by Raymond Duchamp-Villon and then in 1914 by Jacques Lipchitz, Henri Laurens and Ossip Zadkine.


A significant modification of Cubism between 1914 and 1916 was signaled by a shift towards a strong emphasis on large overlapping geometric planes and flat surface activity. This grouping of styles of painting and sculpture, especially significant between 1917 and 1920, was practiced by several artists; particularly those under contract with the art dealer and collector Léonce Rosenberg. The tightening of the compositions, the clarity and sense of order reflected in these works, led to its being referred to by the critic Maurice Raynal (fr) as 'crystal' Cubism. Considerations manifested by Cubists prior to the outset of World War I—such as the fourth dimension, dynamism of modern life, the occult, and Henri Bergson's concept of duration—had now been vacated, replaced by a purely formal frame of reference.


The most innovative period of Cubism was before 1914. After World War I, with the support given by the dealer Léonce Rosenberg, Cubism returned as a central issue for artists, and continued as such until the mid-1920s when its avant-garde status was rendered questionable by the emergence of geometric abstraction and Surrealism in Paris. Many Cubists, including Picasso, Braque, Gris, Léger, Gleizes, and Metzinger, while developing other styles, returned periodically to Cubism, even well after 1925. Cubism reemerged during the 1920s and the 1930s in the work of the American Stuart Davis and the Englishman Ben Nicholson. In France, however, Cubism experienced a decline beginning in about 1925. Léonce Rosenberg exhibited not only the artists stranded by Kahnweiler’s exile but others including Laurens, Lipchitz, Metzinger, Gleizes, Csaky, Herbin and Severini. In 1918 Rosenberg presented a series of Cubist exhibitions at his Galerie de l’Effort Moderne in Paris. Attempts were made by Louis Vauxcelles to claim that Cubism was dead, but these exhibitions, along with a well-organized Cubist show at the 1920 Salon des Indépendants and a revival of the Salon de la Section d’Or in the same year, demonstrated it was still alive.


The reemergence of Cubism coincided with the appearance from about 1917–24 of a coherent body of theoretical writing by Pierre Reverdy, Maurice Raynal and Daniel-Henry Kahnweiler and, among the artists, by Gris, Léger and Gleizes. The occasional return to classicism—figurative work either exclusively or alongside Cubist work—experienced by many artists during this period (called Neoclassicism) has been linked to the tendency to evade the realities of the war and also to the cultural dominance of a classical or Latin image of France during and immediately following the war. Cubism after 1918 can be seen as part of a wide ideological shift towards conservatism in both French society and culture. Yet, Cubism itself remained evolutionary both within the oeuvre of individual artists, such as Gris and Metzinger, and across the work of artists as different from each other as Braque, Léger and Gleizes. Cubism as a publicly debated movement became relatively unified and open to definition. Its theoretical purity made it a gauge against which such diverse tendencies as Realism or Naturalism, Dada, Surrealism and abstraction could be compared.


Cubism formed an important link between early-20th-century art and architecture. The historical, theoretical, and socio-political relationships between avant-garde practices in painting, sculpture and architecture had early ramifications in France, Germany, the Netherlands and Czechoslovakia. Though there are many points of intersection between Cubism and architecture, only a few direct links between them can be drawn. Most often the connections are made by reference to shared formal characteristics: faceting of form, spatial ambiguity, transparency, and multiplicity.


Architectural interest in Cubism centered on the dissolution and reconstitution of three-dimensional form, using simple geometric shapes, juxtaposed without the illusions of classical perspective. Diverse elements could be superimposed, made transparent or penetrate one another, while retaining their spatial relationships. Cubism had become an influential factor in the development of modern architecture from 1912 (La Maison Cubiste, by Raymond Duchamp-Villon and André Mare) onwards, developing in parallel with architects such as Peter Behrens and Walter Gropius, with the simplification of building design, the use of materials appropriate to industrial production, and the increased use of glass.


Cubism was relevant to an architecture seeking a style that needed not refer to the past. Thus, what had become a revolution in both painting and sculpture was applied as part of "a profound reorientation towards a changed world". The Cubo-Futurist ideas of Filippo Tommaso Marinetti influenced attitudes in avant-garde architecture. The influential De Stijl movement embraced the aesthetic principles of Neo-plasticism developed by Piet Mondrian under the influence of Cubism in Paris. De Stijl was also linked by Gino Severini to Cubist theory through the writings of Albert Gleizes. However, the linking of basic geometric forms with inherent beauty and ease of industrial application—which had been prefigured by Marcel Duchamp from 1914—was left to the founders of Purism, Amédée Ozenfant and Charles-Édouard Jeanneret (better known as Le Corbusier,) who exhibited paintings together in Paris and published Après le cubisme in 1918. Le Corbusier's ambition had been to translate the properties of his own style of Cubism to architecture. Between 1918 and 1922, Le Corbusier concentrated his efforts on Purist theory and painting. In 1922, Le Corbusier and his cousin Jeanneret opened a studio in Paris at 35 rue de Sèvres. His theoretical studies soon advanced into many different architectural projects.


At the 1912 Salon d'Automne an architectural installation was exhibited that quickly became known as Maison Cubiste (Cubist House), signed Raymond Duchamp-Villon and André Mare along with a group of collaborators. Metzinger and Gleizes in Du "Cubisme", written during the assemblage of the "Maison Cubiste", wrote about the autonomous nature of art, stressing the point that decorative considerations should not govern the spirit of art. Decorative work, to them, was the "antithesis of the picture". "The true picture" wrote Metzinger and Gleizes, "bears its raison d'être within itself. It can be moved from a church to a drawing-room, from a museum to a study. Essentially independent, necessarily complete, it need not immediately satisfy the mind: on the contrary, it should lead it, little by little, towards the fictitious depths in which the coordinative light resides. It does not harmonize with this or that ensemble; it harmonizes with things in general, with the universe: it is an organism...". "Mare's ensembles were accepted as frames for Cubist works because they allowed paintings and sculptures their independence", writes Christopher Green, "creating a play of contrasts, hence the involvement not only of Gleizes and Metzinger themselves, but of Marie Laurencin, the Duchamp brothers (Raymond Duchamp-Villon designed the facade) and Mare's old friends Léger and Roger La Fresnaye". La Maison Cubiste was a fully furnished house, with a staircase, wrought iron banisters, a living room—the Salon Bourgeois, where paintings by Marcel Duchamp, Metzinger (Woman with a Fan), Gleizes, Laurencin and Léger were hung—and a bedroom. It was an example of L'art décoratif, a home within which Cubist art could be displayed in the comfort and style of modern, bourgeois life. Spectators at the Salon d'Automne passed through the full-scale 10-by-3-meter plaster model of the ground floor of the facade, designed by Duchamp-Villon. This architectural installation was subsequently exhibited at the 1913 Armory Show, New York, Chicago and Boston, listed in the catalogue of the New York exhibit as Raymond Duchamp-Villon, number 609, and entitled "Facade architectural, plaster" (Façade architecturale).


The original Cubist architecture is very rare. There is only one country in the world where Cubism was really applied to architecture – namely Bohemia (today Czech Republic) and especially its capital, Prague. Czech architects were the first and only ones in the world to ever design original Cubist buildings. Cubist architecture flourished for the most part between 1910–1914, but the Cubist or Cubism-influenced buildings were also built after the World War I. After the war, the architectural style called Rondo-Cubism was developed in Prague fusing the Cubist architecture with round shapes.


In their theoretical rules, the Cubist architects expressed the requirement of dynamism, which would surmount the matter and calm contained in it, through a creative idea, so that the result would evoke feelings of dynamism and expressive plasticity in the viewer. This should be achieved by shapes derived from pyramids, cubes and prisms, by arrangements and compositions of oblique surfaces, mainly triangular, sculpted facades in protruding crystal-like units, reminiscent of the so-called diamond cut, or even cavernous that are reminiscent of the late Gothic architecture. In this way, the entire surfaces of the facades including even the gables and dormers are sculpted. The grilles as well as other architectural ornaments attain a three-dimensional form. Thus, new forms of windows and doors were also created, e. g. hexagonal windows. Czech Cubist architects also designed Cubist furniture.


The leading Cubist architects were Pavel Janák, Josef Gočár, Vlastislav Hofman, Emil Králíček and Josef Chochol. They worked mostly in Prague but also in other Bohemian towns. The best-known Cubist building is the House of the Black Madonna in the Old Town of Prague built in 1912 by Josef Gočár with the only Cubist café in the world, Grand Café Orient. Vlastislav Hofman built the entrance pavilions of Ďáblice Cemetery in 1912–1914, Josef Chochol designed several residential houses under Vyšehrad. A Cubist streetlamp has also been preserved near the Wenceslas Square, designed by Emil Králíček in 1912, who also built the Diamond House in the New Town of Prague around 1913.


The influence of cubism extended to other artistic fields, outside painting and sculpture. In literature, the written works of Gertrude Stein employ repetition and repetitive phrases as building blocks in both passages and whole chapters. Most of Stein's important works utilize this technique, including the novel The Making of Americans (1906–08). Not only were they the first important patrons of Cubism, Gertrude Stein and her brother Leo were also important influences on Cubism as well. Picasso in turn was an important influence on Stein's writing.


The poets generally associated with Cubism are Guillaume Apollinaire, Blaise Cendrars, Jean Cocteau, Max Jacob, André Salmon and Pierre Reverdy. As American poet Kenneth Rexroth explains, Cubism in poetry "is the conscious, deliberate dissociation and recombination of elements into a new artistic entity made self-sufficient by its rigorous architecture. This is quite different from the free association of the Surrealists and the combination of unconscious utterance and political nihilism of Dada." Nonetheless, the Cubist poets' influence on both Cubism and the later movements of Dada and Surrealism was profound; Louis Aragon, founding member of Surrealism, said that for Breton, Soupault, Éluard and himself, Reverdy was "our immediate elder, the exemplary poet." Though not as well remembered as the Cubist painters, these poets continue to influence and inspire; American poets John Ashbery and Ron Padgett have recently produced new translations of Reverdy's work. Wallace Stevens' "Thirteen Ways of Looking at a Blackbird" is also said to demonstrate how cubism's multiple perspectives can be translated into poetry.


Chinese political philosophy dates back to the Spring and Autumn Period, specifically with Confucius in the 6th century BC. Chinese political philosophy was developed as a response to the social and political breakdown of the country characteristic of the Spring and Autumn Period and the Warring States period. The major philosophies during the period, Confucianism, Legalism, Mohism, Agrarianism and Taoism, each had a political aspect to their philosophical schools. Philosophers such as Confucius, Mencius, and Mozi, focused on political unity and political stability as the basis of their political philosophies. Confucianism advocated a hierarchical, meritocratic government based on empathy, loyalty, and interpersonal relationships. Legalism advocated a highly authoritarian government based on draconian punishments and laws. Mohism advocated a communal, decentralized government centered on frugality and ascetism. The Agrarians advocated a peasant utopian communalism and egalitarianism. Taoism advocated a proto-anarchism. Legalism was the dominant political philosophy of the Qin Dynasty, but was replaced by State Confucianism in the Han Dynasty. Prior to China's adoption of communism, State Confucianism remained the dominant political philosophy of China up to the 20th century.


Western political philosophy originates in the philosophy of ancient Greece, where political philosophy dates back to at least Plato. Ancient Greece was dominated by city-states, which experimented with various forms of political organization, grouped by Plato into four categories: timocracy, tyranny, democracy and oligarchy. One of the first, extremely important classical works of political philosophy is Plato's Republic, which was followed by Aristotle's Nichomachean Ethics and Politics. Roman political philosophy was influenced by the Stoics, including the Roman statesman Cicero.


Indian political philosophy evolved in ancient times and demarcated a clear distinction between (1) nation and state (2) religion and state. The constitutions of Hindu states evolved over time and were based on political and legal treatises and prevalent social institutions. The institutions of state were broadly divided into governance, administration, defense, law and order. Mantranga, the principal governing body of these states, consisted of the King, Prime Minister, Commander in chief of army, Chief Priest of the King. The Prime Minister headed the committee of ministers along with head of executive (Maha Amatya).


Chanakya, 4th Century BC Indian political philosopher. The Arthashastra provides an account of the science of politics for a wise ruler, policies for foreign affairs and wars, the system of a spy state and surveillance and economic stability of the state. Chanakya quotes several authorities including Bruhaspati, Ushanas, Prachetasa Manu, Parasara, and Ambi, and described himself as a descendant of a lineage of political philosophers, with his father Chanaka being his immediate predecessor. Another influential extant Indian treatise on political philosophy is the Sukra Neeti. An example of a code of law in ancient India is the Manusmṛti or Laws of Manu.


The early Christian philosophy of Augustine of Hippo was heavily influenced by Plato. A key change brought about by Christian thought was the moderatation of the Stoicism and theory of justice of the Roman world, as well emphasis on the role of the state in applying mercy as a moral example. Augustine also preached that one was not a member of his or her city, but was either a citizen of the City of God (Civitas Dei) or the City of Man (Civitas Terrena). Augustine's City of God is an influential work of this period that attacked the thesis, held by many Christian Romans, that the Christian view could be realized on Earth.


The rise of Islam, based on both the Qur'an and Muhammad strongly altered the power balances and perceptions of origin of power in the Mediterranean region. Early Islamic philosophy emphasized an inexorable link between science and religion, and the process of ijtihad to find truth—in effect all philosophy was "political" as it had real implications for governance. This view was challenged by the "rationalist" Mutazilite philosophers, who held a more Hellenic view, reason above revelation, and as such are known to modern scholars as the first speculative theologians of Islam; they were supported by a secular aristocracy who sought freedom of action independent of the Caliphate. By the late ancient period, however, the "traditionalist" Asharite view of Islam had in general triumphed. According to the Asharites, reason must be subordinate to the Quran and the Sunna.


Islamic political philosophy, was, indeed, rooted in the very sources of Islam—i.e., the Qur'an and the Sunnah, the words and practices of Muhammad—thus making it essentially theocratic. However, in the Western thought, it is generally supposed that it was a specific area peculiar merely to the great philosophers of Islam: al-Kindi (Alkindus), al-Farabi (Abunaser), İbn Sina (Avicenna), Ibn Bajjah (Avempace), Ibn Rushd (Averroes), and Ibn Khaldun. The political conceptions of Islam such as kudrah (power), sultan, ummah, cemaa (obligation)-and even the "core" terms of the Qur'an—i.e., ibadah (worship), din (religion), rab (master) and ilah (deity)—is taken as the basis of an analysis. Hence, not only the ideas of the Muslim political philosophers but also many other jurists and ulama posed political ideas and theories. For example, the ideas of the Khawarij in the very early years of Islamic history on Khilafa and Ummah, or that of Shia Islam on the concept of Imamah are considered proofs of political thought. The clashes between the Ehl-i Sunna and Shia in the 7th and 8th centuries had a genuine political character.


Medieval political philosophy in Europe was heavily influenced by Christian thinking. It had much in common with the Mutazalite Islamic thinking in that the Roman Catholics though subordinating philosophy to theology did not subject reason to revelation but in the case of contradictions, subordinated reason to faith as the Asharite of Islam. The Scholastics by combining the philosophy of Aristotle with the Christianity of St. Augustine emphasized the potential harmony inherent in reason and revelation. Perhaps the most influential political philosopher of medieval Europe was St. Thomas Aquinas who helped reintroduce Aristotle's works, which had only been transmitted to Catholic Europe through Muslim Spain, along with the commentaries of Averroes. Aquinas's use of them set the agenda, for scholastic political philosophy dominated European thought for centuries even unto the Renaissance.


One of the most influential works during this burgeoning period was Niccolò Machiavelli's The Prince, written between 1511–12 and published in 1532, after Machiavelli's death. That work, as well as The Discourses, a rigorous analysis of the classical period, did much to influence modern political thought in the West. A minority (including Jean-Jacques Rousseau) interpreted The Prince as a satire meant to be given to the Medici after their recapture of Florence and their subsequent expulsion of Machiavelli from Florence. Though the work was written for the di Medici family in order to perhaps influence them to free him from exile, Machiavelli supported the Republic of Florence rather than the oligarchy of the di Medici family. At any rate, Machiavelli presents a pragmatic and somewhat consequentialist view of politics, whereby good and evil are mere means used to bring about an end—i.e., the secure and powerful state. Thomas Hobbes, well known for his theory of the social contract, goes on to expand this view at the start of the 17th century during the English Renaissance. Although neither Machiavelli nor Hobbes believed in the divine right of kings, they both believed in the inherent selfishness of the individual. It was necessarily this belief that led them to adopt a strong central power as the only means of preventing the disintegration of the social order.


These theorists were driven by two basic questions: one, by what right or need do people form states; and two, what the best form for a state could be. These fundamental questions involved a conceptual distinction between the concepts of "state" and "government." It was decided that "state" would refer to a set of enduring institutions through which power would be distributed and its use justified. The term "government" would refer to a specific group of people who occupied the institutions of the state, and create the laws and ordinances by which the people, themselves included, would be bound. This conceptual distinction continues to operate in political science, although some political scientists, philosophers, historians and cultural anthropologists have argued that most political action in any given society occurs outside of its state, and that there are societies that are not organized into states that nevertheless must be considered in political terms. As long as the concept of natural order was not introduced, the social sciences could not evolve independently of theistic thinking. Since the cultural revolution of the 17th century in England, which spread to France and the rest of Europe, society has been considered subject to natural laws akin to the physical world.


Political and economic relations were drastically influenced by these theories as the concept of the guild was subordinated to the theory of free trade, and Roman Catholic dominance of theology was increasingly challenged by Protestant churches subordinate to each nation-state, which also (in a fashion the Roman Catholic Church often decried angrily) preached in the vulgar or native language of each region. However, the enlightenment was an outright attack on religion, particularly Christianity. The most outspoken critic of the church in France was François Marie Arouet de Voltaire, a representative figure of the enlightenment. After Voltaire, religion would never be the same again in France.


In the Ottoman Empire, these ideological reforms did not take place and these views did not integrate into common thought until much later. As well, there was no spread of this doctrine within the New World and the advanced civilizations of the Aztec, Maya, Inca, Mohican, Delaware, Huron and especially the Iroquois. The Iroquois philosophy in particular gave much to Christian thought of the time and in many cases actually inspired some of the institutions adopted in the United States: for example, Benjamin Franklin was a great admirer of some of the methods of the Iroquois Confederacy, and much of early American literature emphasized the political philosophy of the natives.


John Locke in particular exemplified this new age of political theory with his work Two Treatises of Government. In it Locke proposes a state of nature theory that directly complements his conception of how political development occurs and how it can be founded through contractual obligation. Locke stood to refute Sir Robert Filmer's paternally founded political theory in favor of a natural system based on nature in a particular given system. The theory of the divine right of kings became a passing fancy, exposed to the type of ridicule with which John Locke treated it. Unlike Machiavelli and Hobbes but like Aquinas, Locke would accept Aristotle's dictum that man seeks to be happy in a state of social harmony as a social animal. Unlike Aquinas's preponderant view on the salvation of the soul from original sin, Locke believes man's mind comes into this world as tabula rasa. For Locke, knowledge is neither innate, revealed nor based on authority but subject to uncertainty tempered by reason, tolerance and moderation. According to Locke, an absolute ruler as proposed by Hobbes is unnecessary, for natural law is based on reason and seeking peace and survival for man.


The Marxist critique of capitalism — developed with Friedrich Engels — was, alongside liberalism and fascism, one of the defining ideological movements of the Twentieth Century. The industrial revolution produced a parallel revolution in political thought. Urbanization and capitalism greatly reshaped society. During this same period, the socialist movement began to form. In the mid-19th century, Marxism was developed, and socialism in general gained increasing popular support, mostly from the urban working class. Without breaking entirely from the past, Marx established principles that would be used by future revolutionaries of the 20th century namely Vladimir Lenin, Mao Zedong, Ho Chi Minh, and Fidel Castro. Though Hegel's philosophy of history is similar to Immanuel Kant's, and Karl Marx's theory of revolution towards the common good is partly based on Kant's view of history—Marx declared that he was turning Hegel's dialectic, which was "standing on its head", "the right side up again". Unlike Marx who believed in historical materialism, Hegel believed in the Phenomenology of Spirit. By the late 19th century, socialism and trade unions were established members of the political landscape. In addition, the various branches of anarchism, with thinkers such as Mikhail Bakunin, Pierre-Joseph Proudhon or Peter Kropotkin, and syndicalism also gained some prominence. In the Anglo-American world, anti-imperialism and pluralism began gaining currency at the turn of the 20th century.


World War I was a watershed event in human history, changing views of governments and politics. The Russian Revolution of 1917 (and similar, albeit less successful, revolutions in many other European countries) brought communism - and in particular the political theory of Leninism, but also on a smaller level Luxemburgism (gradually) - on the world stage. At the same time, social democratic parties won elections and formed governments for the first time, often as a result of the introduction of universal suffrage. However, a group of central European economists led by Austrian School economists Ludwig von Mises and Friedrich Hayek identified the collectivist underpinnings to the various new socialist and fascist doctrines of government power as being different brands of political totalitarianism.


From the end of World War II until 1971, when John Rawls published A Theory of Justice, political philosophy declined in the Anglo-American academic world, as analytic philosophers expressed skepticism about the possibility that normative judgments had cognitive content, and political science turned toward statistical methods and behavioralism. In continental Europe, on the other hand, the postwar decades saw a huge blossoming of political philosophy, with Marxism dominating the field. This was the time of Jean-Paul Sartre and Louis Althusser, and the victories of Mao Zedong in China and Fidel Castro in Cuba, as well as the events of May 1968 led to increased interest in revolutionary ideology, especially by the New Left. A number of continental European émigrés to Britain and the United States—including Karl Popper, Friedrich Hayek, Leo Strauss, Isaiah Berlin, Eric Voegelin and Judith Shklar—encouraged continued study in political philosophy in the Anglo-American world, but in the 1950s and 1960s they and their students remained at odds with the analytic establishment.


Communism remained an important focus especially during the 1950s and 1960s. Colonialism and racism were important issues that arose. In general, there was a marked trend towards a pragmatic approach to political issues, rather than a philosophical one. Much academic debate regarded one or both of two pragmatic topics: how (or whether) to apply utilitarianism to problems of political policy, or how (or whether) to apply economic models (such as rational choice theory) to political issues. The rise of feminism, LGBT social movements and the end of colonial rule and of the political exclusion of such minorities as African Americans and sexual minorities in the developed world has led to feminist, postcolonial, and multicultural thought becoming significant. This led to a challenge to the social contract by philosophers Charles W. Mills in his book The Racial Contract and Carole Patemen in her book The Sexual Contract that the social contract excluded persons of colour and women respectively.


In Anglo-American academic political philosophy, the publication of John Rawls's A Theory of Justice in 1971 is considered a milestone. Rawls used a thought experiment, the original position, in which representative parties choose principles of justice for the basic structure of society from behind a veil of ignorance. Rawls also offered a criticism of utilitarian approaches to questions of political justice. Robert Nozick's 1974 book Anarchy, State, and Utopia, which won a National Book Award, responded to Rawls from a libertarian perspective and gained academic respectability for libertarian viewpoints.


Contemporaneously with the rise of analytic ethics in Anglo-American thought, in Europe several new lines of philosophy directed at critique of existing societies arose between the 1950s and 1980s. Most of these took elements of Marxist economic analysis, but combined them with a more cultural or ideological emphasis. Out of the Frankfurt School, thinkers like Herbert Marcuse, Theodor W. Adorno, Max Horkheimer, and Jürgen Habermas combined Marxian and Freudian perspectives. Along somewhat different lines, a number of other continental thinkers—still largely influenced by Marxism—put new emphases on structuralism and on a "return to Hegel". Within the (post-) structuralist line (though mostly not taking that label) are thinkers such as Gilles Deleuze, Michel Foucault, Claude Lefort, and Jean Baudrillard. The Situationists were more influenced by Hegel; Guy Debord, in particular, moved a Marxist analysis of commodity fetishism to the realm of consumption, and looked at the relation between consumerism and dominant ideology formation.


Another debate developed around the (distinct) criticisms of liberal political theory made by Michael Walzer, Michael Sandel and Charles Taylor. The liberal-communitarian debate is often considered valuable for generating a new set of philosophical problems, rather than a profound and illuminating clash of perspective.These and other communitarians (such as Alasdair MacIntyre and Daniel A. Bell) argue that, contra liberalism, communities are prior to individuals and therefore should be the center of political focus. Communitarians tend to support greater local control as well as economic and social policies which encourage the growth of social capital.


A pair of overlapping political perspectives arising toward the end of the 20th century are republicanism (or neo- or civic-republicanism) and the capability approach. The resurgent republican movement aims to provide an alternate definition of liberty from Isaiah Berlin's positive and negative forms of liberty, namely "liberty as non-domination." Unlike liberals who understand liberty as "non-interference," "non-domination" entails individuals not being subject to the arbitrary will of anyother person. To a liberal, a slave who is not interfered with may be free, yet to a republican the mere status as a slave, regardless of how that slave is treated, is objectionable. Prominent republicans include historian Quentin Skinner, jurist Cass Sunstein, and political philosopher Philip Pettit. The capability approach, pioneered by economists Mahbub ul Haq and Amartya Sen and further developed by legal scholar Martha Nussbaum, understands freedom under allied lines: the real-world ability to act. Both the capability approach and republicanism treat choice as something which must be resourced. In other words, it is not enough to be legally able to do something, but to have the real option of doing it.


An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure. Zintl phases are also sometimes considered alloys depending on bond types (see also: Van Arkel-Ketelaar triangle for information on classifying bonding in binary compounds).


An alloy is a mixture of either pure or fairly pure chemical elements, which forms an impure substance (admixture) that retains the characteristics of a metal. An alloy is distinct from an impure metal, such as wrought iron, in that, with an alloy, the added impurities are usually desirable and will typically have some useful benefit. Alloys are made by mixing two or more elements; at least one of which being a metal. This is usually called the primary metal or the base metal, and the name of this metal may also be the name of the alloy. The other constituents may or may not be metals but, when mixed with the molten base, they will be soluble, dissolving into the mixture.


When the alloy cools and solidifies (crystallizes), its mechanical properties will often be quite different from those of its individual constituents. A metal that is normally very soft and malleable, such as aluminium, can be altered by alloying it with another soft metal, like copper. Although both metals are very soft and ductile, the resulting aluminium alloy will be much harder and stronger. Adding a small amount of non-metallic carbon to iron produces an alloy called steel. Due to its very-high strength and toughness (which is much higher than pure iron), and its ability to be greatly altered by heat treatment, steel is one of the most common alloys in modern use. By adding chromium to steel, its resistance to corrosion can be enhanced, creating stainless steel, while adding silicon will alter its electrical characteristics, producing silicon steel.


Although the elements usually must be soluble in the liquid state, they may not always be soluble in the solid state. If the metals remain soluble when solid, the alloy forms a solid solution, becoming a homogeneous structure consisting of identical crystals, called a phase. If the mixture cools and the constituents become insoluble, they may separate to form two or more different types of crystals, creating a heterogeneous microstructure of different phases. However, in other alloys, the insoluble elements may not separate until after crystallization occurs. These alloys are called intermetallic alloys because, if cooled very quickly, they first crystallize as a homogeneous phase, but they are supersaturated with the secondary constituents. As time passes, the atoms of these supersaturated alloys separate within the crystals, forming intermetallic phases that serve to reinforce the crystals internally.


Some alloys occur naturally, such as electrum, which is an alloy that is native to Earth, consisting of silver and gold. Meteorites are sometimes made of naturally occurring alloys of iron and nickel, but are not native to the Earth. One of the first alloys made by humans was bronze, which is made by mixing the metals tin and copper. Bronze was an extremely useful alloy to the ancients, because it is much stronger and harder than either of its components. Steel was another common alloy. However, in ancient times, it could only be created as an accidental byproduct from the heating of iron ore in fires (smelting) during the manufacture of iron. Other ancient alloys include pewter, brass and pig iron. In the modern age, steel can be created in many forms. Carbon steel can be made by varying only the carbon content, producing soft alloys like mild steel or hard alloys like spring steel. Alloy steels can be made by adding other elements, such as molybdenum, vanadium or nickel, resulting in alloys such as high-speed steel or tool steel. Small amounts of manganese are usually alloyed with most modern-steels because of its ability to remove unwanted impurities, like phosphorus, sulfur and oxygen, which can have detrimental effects on the alloy. However, most alloys were not created until the 1900s, such as various aluminium, titanium, nickel, and magnesium alloys. Some modern superalloys, such as incoloy, inconel, and hastelloy, may consist of a multitude of different components.


The term alloy is used to describe a mixture of atoms in which the primary constituent is a metal. The primary metal is called the base, the matrix, or the solvent. The secondary constituents are often called solutes. If there is a mixture of only two types of atoms, not counting impurities, such as a copper-nickel alloy, then it is called a binary alloy. If there are three types of atoms forming the mixture, such as iron, nickel and chromium, then it is called a ternary alloy. An alloy with four constituents is a quaternary alloy, while a five-part alloy is termed a quinary alloy. Because the percentage of each constituent can be varied, with any mixture the entire range of possible variations is called a system. In this respect, all of the various forms of an alloy containing only two constituents, like iron and carbon, is called a binary system, while all of the alloy combinations possible with a ternary alloy, such as alloys of iron, carbon and chromium, is called a ternary system.


Although an alloy is technically an impure metal, when referring to alloys, the term "impurities" usually denotes those elements which are not desired. These impurities are often found in the base metals or the solutes, but they may also be introduced during the alloying process. For instance, sulfur is a common impurity in steel. Sulfur combines readily with iron to form iron sulfide, which is very brittle, creating weak spots in the steel. Lithium, sodium and calcium are common impurities in aluminium alloys, which can have adverse effects on the structural integrity of castings. Conversely, otherwise pure-metals that simply contain unwanted impurities are often called "impure metals" and are not usually referred to as alloys. Oxygen, present in the air, readily combines with most metals to form metal oxides; especially at higher temperatures encountered during alloying. Great care is often taken during the alloying process to remove excess impurities, using fluxes, chemical additives, or other methods of extractive metallurgy.


The term "alloy" is sometimes used in everyday speech as a synonym for a particular alloy. For example, automobile wheels made of an aluminium alloy are commonly referred to as simply "alloy wheels", although in point of fact steels and most other metals in practical use are also alloys. Steel is such a common alloy that many items made from it, like wheels, barrels, or girders, are simply referred to by the name of the item, assuming it is made of steel. When made from other materials, they are typically specified as such, (i.e.: "bronze wheel," "plastic barrel," or "wood girder").


Alloying a metal is done by combining it with one or more other metals or non-metals that often enhance its properties. For example, steel is stronger than iron, its primary element. The electrical and thermal conductivity of alloys is usually lower than that of the pure metals. The physical properties, such as density, reactivity, Young's modulus of an alloy may not differ greatly from those of its elements, but engineering properties such as tensile strength and shear strength may be substantially different from those of the constituent materials. This is sometimes a result of the sizes of the atoms in the alloy, because larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit marked differences in behavior even when small amounts of one element are present. For example, impurities in semiconducting ferromagnetic alloys lead to different properties, as first predicted by White, Hogan, Suhl, Tian Abrie and Nakamura. Some alloys are made by melting and mixing two or more metals. Bronze, an alloy of copper and tin, was the first alloy discovered, during the prehistoric period now known as the bronze age; it was harder than pure copper and originally used to make tools and weapons, but was later superseded by metals and alloys with better properties. In later times bronze has been used for ornaments, bells, statues, and bearings. Brass is an alloy made from copper and zinc.


Alloys are often made to alter the mechanical properties of the base metal, to induce hardness, toughness, ductility, or other desired properties. Most metals and alloys can be work hardened by creating defects in their crystal structure. These defects are created during plastic deformation, such as hammering or bending, and are permanent unless the metal is recrystallized. However, some alloys can also have their properties altered by heat treatment. Nearly all metals can be softened by annealing, which recrystallizes the alloy and repairs the defects, but not as many can be hardened by controlled heating and cooling. Many alloys of aluminium, copper, magnesium, titanium, and nickel can be strengthened to some degree by some method of heat treatment, but few respond to this to the same degree that steel does.


At a certain temperature, (usually between 1,500 °F (820 °C) and 1,600 °F (870 °C), depending on carbon content), the base metal of steel undergoes a change in the arrangement of the atoms in its crystal matrix, called allotropy. This allows the small carbon atoms to enter the interstices of the iron crystal, diffusing into the iron matrix. When this happens, the carbon atoms are said to be in solution, or mixed with the iron, forming a single, homogeneous, crystalline phase called austenite. If the steel is cooled slowly, the iron will gradually change into its low temperature allotrope. When this happens the carbon atoms will no longer be soluble with the iron, and will be forced to precipitate out of solution, nucleating into the spaces between the crystals. The steel then becomes heterogeneous, being formed of two phases; the carbon (carbide) phase cementite, and ferrite. This type of heat treatment produces steel that is rather soft and bendable. However, if the steel is cooled quickly the carbon atoms will not have time to precipitate. When rapidly cooled, a diffusionless (martensite) transformation occurs, in which the carbon atoms become trapped in solution. This causes the iron crystals to deform intrinsically when the crystal structure tries to change to its low temperature state, making it very hard and brittle.


Conversely, most heat-treatable alloys are precipitation hardening alloys, which produce the opposite effects that steel does. When heated to form a solution and then cooled quickly, these alloys become much softer than normal, during the diffusionless transformation, and then harden as they age. The solutes in these alloys will precipitate over time, forming intermetallic phases, which are difficult to discern from the base metal. Unlike steel, in which the solid solution separates to form different crystal phases, precipitation hardening alloys separate to form different phases within the same crystal. These intermetallic alloys appear homogeneous in crystal structure, but tend to behave heterogeneous, becoming hard and somewhat brittle.