Kemp and others who doubt Leonardo's hand in the painting attribute it to the Leonardeschi, Leonardo's workshop, believing it to be one of a number of copies of the "Mona Lisa" produced by Leonardo's collaborators, assistants, and pupils, though, as Leonardo biographer Walter Isaacson has noted, "perhaps with an occasional helping hand from the master". In 2010, The Mona Lisa Foundation was founded to investigate if the "Isleworth Mona Lisa" was painted in part by Leonardo, but as an earlier version of the Louvre "Mona Lisa".