gin of the Rocks. It exists in two versions: the one in Paris is earlier and was executed by Leonardo; the one in London is later, and there is controversy as to whether Leonardo participated in its execution. A religious brotherhood in Milan commissioned an altarpiece from Leonardo in 1483, and it is also a matter of argument as to which version is the one commissioned. Some scholars believe that it is the London work and that the Paris version was painted while Leonardo was still in Florence. But this view requires some remarkable coincidences, and the more usual opinion is that the picture in Paris is the original one executed for the Milanese commission and that it was taken away by Leonardo's admirer the king of France and replaced in Milan by the second painting.Although the Virgin of the Rocksis a very original painting, it makes use of a venerable tradition in which the Holy Family is shown in a cave. This setting becomes a vehicle for Leonardo's interests in depicting nature and in dimmed light, which fuses the outlines of separate objects. The artist once commented that one should practice drawing at dusk and in courtyards with walls painted black. The figures in the painting are grouped in a pyramid.The other surviving painting of Leonardo's Milanese years is the Last Supper (1495-1497), commissioned by the duke for the refectory of the convent of S. Maria delle Grazie. Instead of using fresco, the traditional medium for this theme, Leonardo experimented with an oil-based medium, because painting in true fresco makes areas of color appear quite distinct. Unfortunately, his experiment was unsuccessful; the paint did not adhere well to the wall, and within 50 years the scene was reduced to a confused series of spots. What we see today is largely a later reconstruction, but the design is reliable and remarkable. The scene seems at first to be one of tumultuous activity, in response to the dramatic stimulus of Christ's words "One...
