Masyaf is the Assassin order's fortress in the original Assassin's Creed.
Masyaf is a fortified settlement in Syria and the headquarters of the Levantine Assassin Brotherhood during Altaïr's story. Altaïr returns there after missions to report to Al Mualim, receive guidance, and obtain new assignments.
The game uses Masyaf as a central hub contrasting with the larger cities of Jerusalem, Acre, and Damascus. Its mountainous setting and fortress architecture help establish the Brotherhood as a secretive organization with a disciplined hierarchy.
Masyaf is based on a real Syrian town associated in popular history with the Nizari Ismaili community. The game fictionalizes its role and connects it to the broader Assassin mythology. It should not be confused with Alamut, another historically important fortress often associated with the medieval Nizari Ismailis but not Altaïr's main headquarters in the original game.