When was Leonardo da Vinci's bronze horse made?

It was "not" made in Da Vinci time, however this site will explain it all, (small excerpt)

Il Cavallo's story spans five centuries, beginning in 1482, when Ludovico Sforza, the Duke of Milan and Leonardo's patron, commissioned an equestrian statue in honor of his father. Leonardo worked on the statue for 17 years, completing a 24-foot-tall clay sculpture that was to be cast in bronze. However, the political instability of late 15th century Italy proved to be the project's undoing. In 1499, French forces invaded Milan, forcing Ludovico to use the bronze earmarked for the immense statue to build cannons instead. With the Milanese defeated. French archers used the clay model for target practice. What the conquering army didn't destroy was left to the elements. Il Cavallo vanished from the earth to become a little-known footnote in Renaissance history.