Assassin's Creed Revelations primarily takes place in Constantinople, known today as Istanbul.
The game follows Ezio Auditore as he travels to Constantinople in the early sixteenth century to search for keys connected to Altaïr's library in Masyaf. The city is divided into districts and is portrayed as a major crossroads of Ottoman, Byzantine, and international influences.
Sultan Bayezid II's reign provides the political setting, while princes Selim and Suleiman appear in the succession struggle surrounding the Ottoman court. The historical city was renamed Istanbul over time; Constantinople is the name used for the game's period and setting. Revelations also moves between Constantinople and Masyaf, so it is not exclusively set in one location, but Constantinople is its principal urban setting.