ON AUGUST 21, 1911 THE MONA LISA was stolen from the Louvre, not to reappear again until well over two years later when the thief tried to sell the work to a Florentine art dealer. The patriotic Italian workman who had stolen the painting had wanted to bring some of the Italian masterpieces in French collections back to where they belonged, and he had commenced his grand project with the Mona Lisa because, as he explained, “mi sembrava la piú bella” — she seemed to him to be the most beautiful of them all.1 For Bernard Berenson the disappearance of the Mona Lisa brought about a major rebellion against the ideals he had cultivated as a young man. In his early books on the Florentine painters and their drawings he had sung the praises of Leonardo,2 and ever since he was a student at Harvard in the early 1880s he had been a professed devotee of the writings and thought of Walter Pater.3 Pater’s most celebrated prose passage — his evocation of the Mona Lisa — was one of the pieces of nineteenth-century art criticism which had influenced Berenson more than anything else.4 Like so many other people of his generation, he had learnt the text by heart, and his first visits to the Louvre appear to have been as much in honor of Walter Pater as of the Italian masters.