In Assassin's Creed Brotherhood, Ezio Auditore is trying to liberate Rome from the Borgia family. The game is set primarily in Rome during the early 16th century, after the events of Assassin's Creed II.
Rome is controlled by Cesare Borgia and his allies, who use military force and political power to dominate the city and surrounding countryside. Ezio works with the Roman Brotherhood to weaken Borgia influence by destroying military infrastructure, recruiting Assassins, and restoring districts.
The game's Rome is a stylized historical recreation rather than a complete simulation of every neighborhood. Major landmarks include the Colosseum, the Pantheon, Castel Sant'Angelo, and the Vatican area. A common mix-up is confusing Brotherhood's Rome with Assassin's Creed II, whose main Italian locations include Florence, Venice, and Monteriggioni.
Brotherhood also introduced a larger role for recruitable Assassin allies and expanded the series' multiplayer mode.