Masyaf serves as the Assassins' headquarters in the original Assassin's Creed.
In the game's historical storyline, Masyaf is a fortified mountain settlement in the Levant and the home of the Assassin Brotherhood. Altaïr returns there to receive missions, report to Al Mualim, and learn how the organization is connected to the wider conflict with the Templars.
The game places Masyaf within a fictionalized version of the medieval Levant during the Third Crusade. It also features the cities of Jerusalem, Acre, and Damascus as major mission locations. Monteriggioni is associated with Ezio's Italian-era adventures, Constantinople is central to Assassin's Creed: Revelations, and Alamut is a historically important fortress associated with the Nizari Ismaili state rather than the headquarters named in the original game.