In Assassin's Creed II, the Auditore family lives in Florence at the beginning of the game.
Florence introduces Ezio's family, friends, and early life before the story's central tragedy changes his future. The city's Renaissance architecture and political rivalries provide the setting for the opening chapters and several major missions.
Ezio later travels to other Italian locations, including Monteriggioni, San Gimignano, Forlì, Venice, and Rome in connected parts of the wider story. Monteriggioni becomes the Auditore family's refuge and operational base, but it is not their home at the opening.
The distinction matters because Florence and Venice are both prominent in Assassin's Creed II. Florence is the family's starting city, while Venice occupies a substantial later section of Ezio's journey.