Professional life, 1476–1513

Court records of 1476 show that Leonardo and three other young men were charged with sodomy, and acquitted. From that date until 1478 there is no record of his work or even of his whereabouts, although it is assumed that Leonardo had his own workshop in Florence between 1476 and 1481. He was commissioned to paint an altarpiece in 1478 for the Chapel of St Bernard and The Adoration of the Magi in 1481 for the Monks of San Donato a Scopeto.
In 1482 Leonardo helped secure peace between Lorenzo de' Medici and Ludovico il Moro, Duke of Milan. Leonardo wrote a letter to Ludovico, describing his engineering and painting skill. He created a silver lyre in the shape of a horse's head, with which he was sent to Milan.
Leonardo continued work in Milan between 1482 and 1499. He was commissioned to paint the Virgin of the Rocks for the Confraternity of the Immaculate Conception, and The Last Supper for the monastery of Santa Maria delle Grazie. While living in Milan between 1493 and 1495 Leonardo listed a woman called Caterina among his dependents in his taxation documents. When she died in 1495, her list of funeral expenditure suggests that she was his mother.
His work for Ludovico included floats and pageants for special occasions, designs for a dome for Milan Cathedral and a model for a huge equestrian monument to Francesco Sforza, Ludovico's predecessor. Leonardo modelled a huge horse in clay, which became known as the "Gran Cavallo", and surpassed in size the two large equestrian statues of the Renaissance. Seventy tons of bronze were set aside for casting it. The monument remained unfinished for several years, which was not unusual for Leonardo. In 1492 the model was completed, and Leonardo was making detailed plans for its casting. Michelangelo rudely implied that Leonardo was unable to cast it. In November 1494 Ludovico gave the bronze to be used for cannons to defend the city from invasion by Charles VIII.
At the start of the Second Italian War in 1499, the invading French troops used the life-size clay model for the "Gran Cavallo" for target practice. With Ludovico Sforza overthrown, Leonardo, with his assistant Salai and friend, the mathematician Luca Pacioli, fled Milan for Venice, where he was employed as a military architect and engineer, devising methods to defend the city from naval attack.