Which artist co-founded Cubism with Picasso?

Georges Braque, and for about six years the two worked so closely that their canvases from the period are genuinely hard to tell apart - both were deliberately suppressing personal style, both largely stopped signing the fronts, and Braque described it as being roped together like mountaineers.

The name was an insult. A critic described Braque's landscapes as reducing everything to little cubes, and the term stuck the way Impressionism had. What they were actually doing was abandoning the single fixed viewpoint that European painting had used since the Renaissance - showing an object from several angles at once, which sounds like a technical exercise and was really an argument about whether a painting should pretend to be a window.

The partnership ended in 1914 when Braque went to the war. He was badly wounded in the head at Carency, trepanned, temporarily blinded, and returned two years later to a changed art world and a former collaborator who had moved on without him. Picasso did not serve. They remained cordial and never worked together again, and Braque's later reputation has never quite recovered from being the other one.