What fictional artifact lets users control minds in the Assassin's Creed series?

The Apple of Eden is the fictional artifact associated with mind control in Assassin's Creed.

An Apple of Eden is one of the Pieces of Eden, advanced artifacts created by the Isu, the precursor civilization in the series' mythology. Its effects can include controlling or influencing human minds, creating illusions, and projecting energy. Different games present particular Apples and their powers in different ways.

The artifact is central to the conflict between the Assassin Brotherhood and the Templars because both factions seek Pieces of Eden for their competing visions of human freedom and order. The Apple is sometimes confused with other Pieces of Eden, including the Staff, Sword, and Shroud. Those artifacts have distinct forms and abilities, but the Apple is the series' best-known mind-influencing object.