In Assassin's Creed Revelations, what historic name does the game use for Istanbul?

Assassin's Creed Revelations uses the historic name Constantinople for its principal city.

Released in 2011, Revelations follows Ezio Auditore during the early sixteenth century as he searches for Altaïr's sealed library. The city called Constantinople in the game was the capital of the Byzantine Empire and had been conquered by the Ottoman Empire in 1453. The game's setting reflects that Ottoman period, including its districts, markets, waterways, and political factions.

Modern English commonly calls the city Istanbul, but Constantinople was the dominant historical name during the period depicted by Revelations. The game also includes Cappadocia and the mountain fortress of Masyaf, connecting Ezio's journey with Altaïr's earlier story.

Byzantium is an older name associated with the city before Constantine the Great, while Istanbul became the official English usage much later. Those distinctions make Constantinople the specific answer for Revelations' sixteenth-century setting.