Altaïr was a member of the Assassin Order, a faction in opposition to the Knights Templar. Before the Third Crusade, Altaïr was the most skilled Assassin in the entire Order. He was demoted after he failed to assassinate Robert de Sable and led the Templars back to Masyaf. After his demotion, Altaïr's master and leader of the Assassins, Sinan, offered him a task. To regain his former reputation, Altaïr was ordered to kill seven high-ranked Templars scattered throughout the three cities of Acre, Masyaf, and Jerusalem. Sibrand, William of Montferrat and Garnier de Naplouse awaited him in Acre. Altaïr killed Vizier Abull Aswad and Tamir Bin Musa near Masyaf, and killed Maj Aldin, Tallal, and Robert de Sable in Jerusalem. With his reputation restored and his missions completed, Altaïr returned to his master Sinan, only to discover that Sinan was in fact secretly a Templar who had manipulated Altaïr to eliminate Sinan's former allies to consolidate more power for himself. With this revelation of Sinan's betrayal of the Creed, Altaïr was forced to confront and kill his former master. With Sinan dead, Altaïr obtained the treasure he had previously looted from Robert de Sable: the elusive Piece of Eden capable of altering the world's fate.