Da Vinci's Demons--The Intersecting Lives of Da Vinci, Machiavelli, and Borgia
It tells the compelling tale of the events of 1502 when Italy, torn apart by warring factions, was on the brink of political convulsion. Cesare Borgia and his army threatened to take the city of Florence and Machiavelli thought of a way to stop him. He seems to have offered up Da Vinci to become Borgia's military engineer--something that Borgia wanted dearly and Da Vinci had already declined.
It is a story about genius and events that changed world history. These three men, each epitomizing a distinct aspect of humanity, spent time together in 1502 and Strathern masterfully describes the events.