Which historical conflict provides the main backdrop for the first Assassin’s Creed game?

The main historical backdrop of the first Assassin’s Creed game is the Third Crusade.

The game’s historical sequences take place in 1191, during the conflict between forces associated with the Crusader states and the Muslim powers led by Saladin. Altaïr Ibn-La’Ahad, an Assassin, carries out missions in cities including Jerusalem, Acre and Damascus.

The game uses real historical figures and locations while combining them with fictional characters, organizations and events. Robert de Sablé, the Grand Master of the Templars, is one of the historical-fictional figures central to the plot. The narrative does not attempt to reproduce every event of the crusade; it places the Assassin-Templar conflict inside that setting.

The Third Crusade followed the capture of Jerusalem by Saladin in 1187 and included the campaigns of Richard I of England. It should not be confused with the First Crusade, which occurred nearly a century earlier.