The ancient Apple-shaped artifact central to the Assassin's Creed series is the Apple of Eden.
The Apple of Eden is one of the series' Pieces of Eden, powerful artifacts created by the Isu. It is usually depicted as a small sphere and can influence human perception, control minds, create illusions, and project information, depending on the particular Apple and story context.
Pieces of Eden drive much of the conflict between the Assassins and Templars. The Templars generally seek to use them to impose order and control, while the Assassins oppose centralized domination and protect human freedom. Several historical figures and protagonists interact with Apples across different games.
The Apple should not be confused with every artifact called a Piece of Eden. The Spear of Leonidas, Staff of Hermes, and Shroud of Eden are distinct objects with different forms and functions. The term “Apple of Eden” refers specifically to the spherical artifact, not to the entire ancient Isu civilization.