The historical story of the first Assassin’s Creed is primarily set in 1191.
That year falls during the Third Crusade, the medieval conflict that followed the capture of Jerusalem by Saladin in 1187. Altaïr Ibn-La'Ahad carries out missions in cities including Jerusalem, Acre, and Damascus while serving the Assassin Brotherhood.
The game uses historical figures and events as a backdrop but presents a fictional secret-war narrative involving Assassins, Templars, and the Pieces of Eden. The date is sometimes confused with 1099, the year of the First Crusade’s capture of Jerusalem, or 1453, the year Constantinople fell to the Ottoman Empire and the setting associated with later series stories.