In Assassin's Creed Revelations, most of Ezio's story takes place in Constantinople.
The game is set in the early sixteenth century, when Constantinople was the capital of the Ottoman Empire. Ezio travels there to recover Altaïr Ibn-La'Ahad's ancient memory seals and uncover the secrets of the Masyaf fortress.
The city is divided into districts influenced by Ottoman, Byzantine, and other communities. Ezio works with local Assassins, including Yusuf Tazim, while becoming involved in political tensions surrounding Sultan Bayezid II and his sons.
The modern name Istanbul became widespread later, but Constantinople is the historical name used for the game's setting. Revelations was released in 2011 and concludes Ezio's main story while also returning to Altaïr and continuing Desmond's modern-day narrative.