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

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

The story follows Altaïr Ibn-La'Ahad in the year 1191, when the Third Crusade is taking place in the eastern Mediterranean. The major cities visited by Altaïr include Jerusalem, Acre, and Damascus, all represented through the game's fictionalized historical world.

The campaign uses real figures and conflicts as a backdrop for its fictional Assassin-Templar narrative. Altaïr receives targets from the Assassin Bureau and investigates political events surrounding the Crusader and Saracen factions.

The Third Crusade is often confused with the broader medieval period because the game includes many elements associated with medieval warfare and religion. It is more specific than simply calling the setting the Middle Ages. The Renaissance is the era most closely associated with Ezio's later adventures, not Altaïr's first major game.