How did Pablo Picasso and Georges Braque develop Cubism together?

Pablo Picasso and Georges Braque developed Cubism through an intense, daily collaboration between 1907 and 1914, a partnership Braque later likened to being "roped alpinists."123

The foundation of the movement was built on mutual influence:
* Initial Catalyst: Picasso’s 1907 work, Les Demoiselles d’Avignon, provided the initial liberating shock by fracturing forms into angular, distorted planes.12
* Geometric Influence: Braque, deeply inspired by Paul Cézanne, introduced a focus on geometric volumes and tilted planes, most notably in his 1908 landscapes.12
* Analytical Phase: From 1910 to 1912, the artists worked so closely that their paintings became nearly indistinguishable. They systematically broke down objects into complex, overlapping planes, utilizing a subdued, monochromatic palette to emphasize the structure of form over traditional perspective.12
* Synthetic Phase: Starting in 1912, they shifted toward Synthetic Cubism, incorporating collage techniques—such as pasting wallpaper or newspapers onto the canvas—to challenge the distinction between reality and illusion.12

Their collaboration ended with the outbreak of World War I in 1914, after which the two artists never worked together again.1