By 1930, Pablo Picasso, nearing 50, was as rich as Croesus. He was the occupant of a flat and studio in rue La Boétie, in the ritzy 8th arrondissement, owner of a country mansion in the north-west, towards Normandy, and was chauffeured around in an adored Hispano-Suiza. He stored the thousands of French francs from the sale of his work in sacks deep inside a Banque de France vault, like a ‘country bumpkin who keeps his savings sewn into his mattress’, someone once said.