In 1487 he was again resident in Milan as general artificer—using that term in its widest sense—to Ludovico. Among his various activities at this period must be mentioned the designs he made for the cupola of the cathedral at Milan, and the scenery he constructed for "Il Paradiso," which was written by Bernardo Bellincioni on the occasion of the marriage of Gian Galeazzo with Isabella of Aragon. About 1489-1490 he began his celebrated "Treatise on Painting" and recommenced work on the colossal equestrian statue of Francesco Sforza, which was doubtless the greatest of all his achievements as a sculptor. It was, however, never cast in bronze, and was ruthlessly destroyed by the French bowmen in April 1500, on their occupation of Milan after the defeat of Ludovico at the battle of Novara. This is all the more regrettable as no single authentic piece of sculpture has come down to us from Leonardo's hand, and we can only judge of his power in this direction from his drawings, and the enthusiastic praise of his contemporaries.

This copy is usually ascribed to Marco d'Oggiono, but some critics claim that it is by Gianpetrino. It is the same size as the original.]