Cubism was one of the first truly modern movements to emerge in art. It evolved during a period of heroic and rapid innovation between Pablo Picasso and Georges Braque. The movement has been described as having two stages: 'Analytic' Cubism, in which forms seem to be 'analyzed' and fragmented; and 'Synthetic' Cubism, in which newspaper and other foreign materials such as chair caning and wood veneer, are collaged to the surface of the canvas as 'synthetic' signs for depicted objects. The style was significantly developed by Fernand Léger and Juan Gris, but it attracted a host of adherents, both in Paris and abroad, and it would go on to influence the Abstract Expressionists, particularly Willem de Kooning.

• Analytic Cubism staged modern art's most radical break with traditional models of representation. It abandoned perspective, which artists had used to order space since the Renaissance. And it turned away from the realistic modeling of figures and towards a system of representing bodies in space that employed small, tilted planes, set in a shallow space. Over time, Picasso and Braque also moved towards open form - they pierced the bodies of their figures, let the space flow through them, and blended background into foreground. Some historians have argued that its innovations represent a response to the changing experience of space, movement, and time in the modern world.
• Synthetic Cubism proved equally important and influential for later artists. Instead of relying on depicted shapes and forms to represent objects, Picasso and Braque began to explore the use of foreign objects as abstract signs. Their use of newspaper would lead later historians to argue that, instead of being concerned above all with form, the artists were also acutely aware of current events - in particular WWI.
• Cubism paved the way for geometric abstract art by putting an entirely new emphasis on the unity between the depicted scene in a picture, and the surface of the canvas. Its innovations would be taken up by the likes of Mondrian, who continued to explore its use of the grid, its abstract system of signs, and its shallow space.

Two events marked the beginning of Cubism. The first was Picasso returning to Paris from his home in Catalonia with his painting, Les Demoiselles d'Avignon (1907). In it's radical distortion of the figures, its rendering of volumes as fragmented planes, and its subdued palette, this work predicted some of the key characteristics of later Cubism. Secondly, Braque made a series of landscape paintings in the summer of 1908, in which trees and mountains were rendered as shaded cubes and pyramids, resembling architectural forms. It was this series that led French art critic Louis Vauxcelles to describe them as "bizarreries cubiques," thus giving the movement its name.

The close contact between Picasso and Braque was crucial in the style's genesis. The two artists collaborated very closely, regularly meeting to discuss their progress, and at times it is hard to distinguish the work of one artist from another. Both were living in Montmartre in the years before and during World War I. The other artists who came to be associated with the style - Robert Delaunay, Henri Le Fauconnier, Jean Metzinger and Albert Gleizes - occupied different social circles, gathered elsewhere around Paris and later exhibited together. This group came to be known as the 'Salon' Cubists.

In its early phase, Cubism developed in a highly systematic fashion. Later to be known as the 'Analytic' period of the style, it was based on close observation of objects in their background contexts. Picasso and Braque restricted their subject matter to the traditional genres of portraiture and still life; they also limited their palette to earth tones and muted silvers, better to maintain clarity between the forms' fragmented planes. Although their work was often very similar in appearance, over time, their separate interests showed through. Braque tended to show objects exploding out or pulled apart into fragments, while Picasso rendered them magnetized, with attracting forces compelling elements of the pictorial space into the center of the composition.

In 1912 both Picasso and Braque began to introduce foreign elements into their compositions. Picasso incorporated chair caning into Still Life with Chair-Caning (1912), initiating Cubist collage, and Braque began to glue newspaper to his canvases, beginning the movement's exploration of papier-colle. In part this may have resulted from the artists' growing discomfort with the radical abstraction of Synthetic Cubism, though it could also be argued that these experiments touched off an even more radical turn away from the real, and towards the use of abstract signs as codes for the real. At this stage, Juan Gris began to make important contributions to the style: he maintained a sharp clarity to his forms, provided suggestions of a compositional grid, and introduced more color to what had hitherto been an austere style.

Cubism spread quickly throughout Europe in the 1910s, as much because of its systematic approach to rendering imagery as the openness it offered in depicting objects in new ways. Critics were split over whether Cubists were concerned to represent imagery in a more objective manner - revealing more of its essential character - or whether they were principally interested in distortion and abstraction. As critics debated Cubism's definitions, artists made work that ranged from analytical explorations of form to the use of codes to communicate a semi-mystical expression of beauty. Some artists, like Fernand Léger, adapted Cubism to formal experiments with mathematical grids. Others, like the Sonia and Robert Delaunay, took an interest in metaphysical notions of a fourth dimension, applying Cubist rules to works that illustrated multiple scenes overlaid onto each another.

The significance of Cubism began to decline in France in the mid 1920s as many of the style's early practitioners would turn to other focuses. Even as the style started to disperse, it would go on to be hugely important in seeding other movements in modern art. It lies at the root of a host of early modern styles such as Dada, Constructivism and Neo-Plasticism, whilst also being the impetus for the later, romantic reactions such as Surrealism, which rejected Cubism's sometimes quasi-scientific approach to perception. The ideas in the movement also fed into more popular phenomena, like Art Deco design and architecture.

"I have transformed myself in the zero of form and fished myself out of the rubbishy slough of Academic Art. I have destroyed the circle of the horizon and escaped from the circle of objects, the horizon-ring that has imprisoned the artist and the forms from nature. The square is not a subconscious form. It is the creation of intuitive reason. The face of the new art. The square is the living, royal infant. It is the first step of pure creation in art.
--Kazimir Malevich, from "From Cubism to Futurism to Suprematism: The New Realism in Painting"

"He commenced the long struggle not to express what he could see but not to express the things he did not see, that is to say the things everybody is certain of seeing but which they do not really see."
--Gertrude Stein, on Picasso's early art