In Assassin's Creed II, Florence is the birthplace of Ezio Auditore da Firenze.
Ezio is introduced as a young nobleman in Florence in 1476. The city forms the opening major setting of his story, where players meet his family, explore Renaissance streets, and witness the events that eventually send him onto the path of the Assassins.
The surname “da Firenze” literally identifies Ezio with Florence. After leaving the city, he travels through several other Italian locations, including Monteriggioni, San Gimignano, Forlì, Venice, and Rome. Venice is especially prominent, which can make it a tempting but incorrect answer.
Assassin's Creed II uses a broad historical setting rather than depicting only one city. Its Florence sections include landmarks such as the Palazzo della Signoria and the Basilica of Santa Croce, while the wider plot links Ezio's personal revenge to the long conflict between Assassins and Templars.