How did Georges Braque and Pablo Picasso work together to develop Cubism?

Georges Braque and Pablo Picasso developed Cubism through an intense, daily exchange of ideas, a partnership Braque later described as being like "roped alpinists."1

Their collaboration evolved through several key stages:

• Foundations: While Picasso provided the initial shock of his proto-Cubist Les Demoiselles d’Avignon, Braque contributed a focus on geometric forms, heavily influenced by the work of Paul Cézanne. By 1908, they were engaged in a process of mutual influence that defined the movement.12
• Analytical Cubism: From 1911, their work became nearly interchangeable. They systematically broke down subjects into facets, eliminated traditional perspective, and utilized a subdued, monochromatic palette to create nearly abstract, complex compositions.1
• Synthetic Cubism: By 1912, they shifted toward Synthetic Cubism, where subject matter became more central. Braque pioneered the use of papier collé by incorporating wallpaper into his drawings, reinforcing the concept that a painting is an autonomous object rather than an illusion.1

Their collaborative work ended with the outbreak of World War I in 1914, after which they never worked together again.1