In the 2007 video game Assassin's Creed, the Assassins' stronghold in the Holy Land is Masyaf.
Masyaf is a fortified mountain settlement in Syria and serves as the headquarters of the Assassin Brotherhood during the game's story. Altaïr Ibn-La'Ahad returns there after missions to receive assignments, report to his mentor, and learn how the political situation is changing.
The game also features three major cities: Jerusalem, Acre, and Damascus. Those cities are mission locations, while Masyaf functions primarily as the Brotherhood's home base. This distinction can cause confusion because the game repeatedly moves between Masyaf and the larger cities.
Historically, Masyaf is associated with the medieval Nizari Ismaili community and its fortifications. Assassin's Creed uses that historical setting as the foundation for its fictional Brotherhood, adding characters and events created for the game.