Which historical conflict provides the setting for the first Assassin's Creed game?

The Third Crusade provides the historical setting for the first Assassin's Creed game.

The game is set primarily in 1191, during the Third Crusade, a conflict involving European Crusader states, Muslim powers, and contested cities in the eastern Mediterranean. Altaïr's missions take him through places including Masyaf, Jerusalem, Acre, and Damascus.

The historical background is used as the framework for a fictional story about the Assassins and Templars. Real leaders and locations appear alongside invented characters, conspiracies, and technology, so the game is historical fiction rather than a documentary account of the Crusade.

The Third Crusade began after the fall of Jerusalem to Saladin in 1187 and included campaigns associated with Richard I of England, Philip II of France, and the Holy Roman Emperor Frederick Barbarossa. Those broader events help anchor the game's political atmosphere.