In Assassin's Creed, Altaïr Ibn-La'Ahad's mentor before he becomes Mentor is Al Mualim.
Al Mualim leads the Assassin Order from Masyaf during the events of the first game. He sends Altaïr on missions against nine important targets during the Third Crusade, while also supervising the training and discipline of the order's members.
The name is sometimes confused with Altaïr's formal title or with the historical setting itself. Al Mualim is a character and leader, not the name of the Assassin headquarters. Masyaf is the mountain settlement where the order is based.
The game's story later reveals that Al Mualim has pursued the Apple of Eden for his own purposes. After Altaïr defeats him, Altaïr takes leadership of the order and begins reforms that shape later Assassin history.