Niccolò Machiavelli
Niccolò di Bernardo dei Machiavelli (3 May 1469 – 21 June 1527) was an Italian philosopher, writer, and is considered one of the main founders of modern political science. He was a diplomat, political philosopher, musician, and playwright, but foremost he was a civil servant of the Florentine Republic.
Assassin's Creed II
Machiavelli appears with Ezio's allies after his battle with Rodrigo Borgia, explaining that he, along with many of Ezio's allies are Assassins. He also is a part of Ezio's Ceremony for becoming an Assassin, performing a Leap of Faith along with the other Assassins. It is possible that he may be the leader of the Assassins.
Though he only makes a small appearance in the original Assassin's Creed II game, he will be with Ezio on both the Battle for Forli and Bonfire of the Vanities episodes (downloadable content). They might have chosen him for the game cause it is known that he was a really sneaky man.