Only a privileged coterie of friends knew the extent of Edgar Degas's passion for collecting. Even fewer were invited to enter the private museum that he set up in the late 1890s in his apartment in Paris, where he hoarded a staggering array of masterpieces by the artists he regarded as his forebears--J.-A.-D. Ingres, Eugène Delacroix, and Honoré Daumier--and by a select group of contemporaries, principally Édouard Manet, Paul Cézanne, Paul Gauguin, and Mary Cassatt. Although Degas inherited some works from his father and acquired a few works through exchange with his friends, the majority of his collection--some one thousand paintings and drawings and four thousand prints--was purchased during the last decade of the nineteenth century. Degas toyed with the idea of founding a public museum for his collection, but it was never realized. By 1901 one friend wrote that Degas's remarkable collection was "closed, defended, shut away, and it is not recommended that you ring at the door unless you are carrying under your arm an unknown Ingres."

Following Degas's death in September 1917, the revelation of his collection as well as the contents of his studio--hundreds of his own paintings and thousands of his drawings and prints--astounded an art world preoccupied with the war advancing across Europe. Upon the announcement that the collection and studio were to be sold at auction, collectors and museums mobilized to attend the eight sales held in Paris over two years to disperse the eight thousand items. The press was stunned by the high prices paid in the sales room while German cannons boomed on the outskirts of the French capital. One writer suggested that an exhibition of all the works should be organized "in three or five years, to know where they ended up."