In Assassin's Creed Brotherhood, Rome is controlled by the Borgia family and rebuilt by Ezio's Brotherhood.
The game takes place primarily in Rome, where Cesare Borgia and his allies exercise political and military power. Much of the city is initially restricted or damaged by Borgia influence. Ezio weakens that control by destroying military assets, eliminating key agents, liberating districts, and rebuilding shops and landmarks.
Rome is also the headquarters of the Italian Assassins during this chapter of Ezio's story. The player recruits and trains new Assassins, then sends them on missions across Europe. This system expands the Brotherhood beyond Ezio's individual work in the city.
Although the narrative includes places such as Monteriggioni and the Vatican area, Rome is the defining setting. The historical Borgias were a powerful Renaissance family, while the game's conflict between Assassins and Templars is fictionalized.