In Assassin's Creed II, which historical artist and inventor becomes Ezio's ally?

In Assassin's Creed II, Leonardo da Vinci becomes Ezio's ally.

Leonardo meets Ezio in Florence and remains an important friend throughout the story. He helps interpret pages from the Codex left by Altaïr Ibn-La'Ahad and uses his engineering knowledge to improve Ezio's equipment. His workshop becomes a recurring place where the player receives information and upgrades.

The game presents Leonardo as both an artist and an inventor, reflecting his historical reputation during the Italian Renaissance. Assassin's Creed II uses real people and places within a fictional story, so Leonardo's collaboration with Ezio is part of the game's imaginative narrative rather than documented history.

Leonardo's involvement also helps connect the Codex, ancient technology, and the broader conflict between Assassins and Templars. Michelangelo, Raphael, and Galileo were real Italian figures, but they are not the particular artist-inventor ally asked about here.