In Assassin's Creed Brotherhood, Ezio controls and rebuilds Rome as the game's main setting.
Rome is the central open-world location of Brotherhood, following Ezio's campaign against the Borgia family. Much of the city begins under Borgia influence, with districts controlled by enemy captains. Ezio can liberate those districts by locating and eliminating the relevant captain, then igniting the district's Borgia tower.
The rebuilding system lets Ezio invest in shops, landmarks, tunnels, and other businesses. These purchases restore the city's economy and generate income over time. Rome's scale and concentration of landmarks distinguish Brotherhood from Assassin's Creed II, which divided its story among Florence, Venice, Forlì, and other Italian locations.
The city also provides the setting for the formal expansion of Ezio's Brotherhood. Recruits from Rome and surrounding areas can be trained and assigned to missions across Europe. The game includes other locations, including Monteriggioni and a short present-day setting, but Rome is the unmistakable main city.