Ludovico Sforza, duke of Milan.
About 1482 Leonardo entered the service of the duke of Milan, Ludovico Sforza, having written the duke an astonishing letter in which he stated that he could build portable bridges; that he knew the techniques of constructing bombardments and of making cannons; that he could build ships as well as armored vehicles, catapults, and other war machines; and that he could execute sculpture in marble, bronze, and clay. He served as principal engineer in the duke's numerous military enterprises and was active also as an architect. In addition, he assisted the Italian mathematician Luca Pacioli in the celebrated work Divina Proportione (1509).
During his long stay in Milan, Leonardo also produced other paintings and drawings (most of which have been lost), theater designs, architectural drawings, and models for the dome of Milan Cathedral. His largest commission was for a colossal bronze monument to Francesco Sforza, father of Ludovico, in the courtyard of CASTELLO SFORZESCO. In December 1499, however, the Sforza family was driven from Milan by French forces; Leonardo left the statue unfinished (it was destroyed by French archers, who used the terra cotta model as a target) and he returned to Florence in 1500.
Castello Sforzesco means "castle of the Sforzas" (the duke's family name)
