Which artifact do the Assassins and Templars pursue in the first Assassin's Creed game?

The artifact pursued in the first Assassin's Creed game is the Apple of Eden.

The Apple of Eden is one of the series’ Pieces of Eden, ancient devices associated with the Isu, the technologically advanced civilization that existed before recorded human history in the franchise’s mythology. The Apple can influence human perception and behavior, making it valuable to both the Assassins and the Templars.

Altaïr’s missions gradually reveal that the targets he eliminates are connected to a larger struggle over this artifact. The game’s historical plot takes place in 1191, during the Third Crusade, while its modern-day storyline follows Desmond Miles and the Animus.

The Apple is often confused with other Pieces of Eden introduced in later games. The Staff of Hermes and the Shroud are separate artifacts, while the Sword of Eden is another powerful Isu weapon. Their shared name does not make them interchangeable.