Readymades of Marcel Duchamp to turn up any identical matches to photographs of the originals. However, there are accounts of Walter Arensberg and Joseph Stella being with Duchamp when he purchased the original "Fountain" at J. L. Mott Iron Works. Such investigations are hampered by the fact that few of the original "readymades" survive, having been lost or destroyed. Those that still exist are predominantly reproductions authorized or designed by Duchamp in the final two decades of his life. Shearer also asserts that the artwork "L.H.O.O.Q." which is recorded to be a poster-copy of the "Mona Lisa" with a moustache drawn on it, is
Marcel Duchamp created the Société Anonyme in 1920, along with Katherine Dreier and Man Ray. This was the beginning of his lifelong involvement in art dealing and collecting. The group collected modern art works, and arranged modern art exhibitions and lectures throughout the 1930s. By this time Walter Pach, one of the coordinators of the 1913 Armory Show, sought Duchamp's advice on modern art. Beginning with Société Anonyme, Dreier also depended on Duchamp's counsel in gathering her collection, as did Arensberg. Later Peggy Guggenheim, Museum of Modern Art directors Alfred Barr and James Johnson Sweeney consulted with Duchamp on their modern art