Which historical conflict forms the backdrop of the first Assassin's Creed game?

The Third Crusade forms the historical backdrop of the first Assassin's Creed game.

The game's historical chapters take place in 1191, during the Third Crusade. Altaïr Ibn-La'Ahad operates across the Levant, including the cities of Masyaf, Jerusalem, Acre, and Damascus. His missions involve political and military figures connected to the conflict, while the fictional Assassin–Templar struggle is woven into the period's real history.

The Third Crusade lasted from 1189 to 1192 and was fought after the Muslim ruler Saladin recaptured Jerusalem in 1187. European leaders including Richard I of England participated in the campaign. The game does not present a straightforward documentary account; it combines historical figures and places with fictional secret societies and supernatural artifacts.

The First Crusade occurred earlier, beginning in 1096, so it is not the game's setting. The Hundred Years' War and Peloponnesian War belong to different centuries and are associated with other historical periods represented elsewhere in the franchise.