The Assassin protagonist of the original Assassin’s Creed is Altaïr Ibn-La'Ahad.
Altaïr is a Syrian Assassin operating in the Holy Land during 1191, amid the Third Crusade. At the beginning of the game, he is demoted after a failed mission and must regain his rank by carrying out assignments for the Assassin Brotherhood.
The game sends Altaïr to major cities including Jerusalem, Acre, and Damascus. His targets are connected to the conflict between the Assassins, the Templars, and the Crusader and Saracen powers. The historical setting is fictionalized, but several political figures and locations draw on the period’s history.
Altaïr is sometimes confused with Ezio Auditore, the protagonist of the next major story arc. Ezio’s adventures take place mainly in Renaissance Italy, while Altaïr’s story establishes the series’ central conflict and introduces the Animus framework.