In Assassin's Creed Brotherhood, which Roman landmark serves as the Borgia family fortress?

Castel Sant'Angelo serves as the Borgia family fortress in Assassin's Creed Brotherhood. The massive cylindrical structure on the Tiber is one of Rome's most important fortified landmarks and becomes a major target in Ezio's campaign.

Historically, Castel Sant'Angelo began as the mausoleum of the Roman emperor Hadrian and was later converted into a military fortress and papal refuge. Brotherhood uses its real defensive character in a fictionalized Renaissance plot, placing Borgia power and resistance inside the building.

The fortress should not be confused with the Colosseum, which is another major Roman landmark and a location visited during the game. The Pantheon also appears in the broader Roman setting, but it is not the Borgia family stronghold. In the game, infiltrating Castel Sant'Angelo is closely connected with the struggle against Cesare Borgia and the papal forces supporting his ambitions.