Masyaf is the Assassin Brotherhood's sanctuary in Assassin's Creed Revelations.
The 2011 game follows Ezio Auditore as he travels to Masyaf, a mountain fortress in modern-day Syria, while searching for Altaïr Ibn-La'Ahad's library. Masyaf was also the headquarters of the Assassin order during the events of the first Assassin's Creed game, making it an important location across the franchise's timeline.
Revelations then moves much of its historical action to Constantinople, where Ezio investigates keys connected to the library and becomes involved in the city's Assassin network. The game alternates among Ezio's sixteenth-century story, Altaïr's earlier memories, and Desmond Miles's modern-day sequences.
Monteriggioni is Ezio's Italian villa and a base in earlier games. The Aquila is a ship associated with Assassin's Creed III, while the Great Library is the destination inside Masyaf rather than the sanctuary's name. This distinction makes Masyaf a particularly important location in the series' shared history.