Spherical Piece of Eden

The spherical Piece of Eden was the artifact stored within the Head of Saint-Denis, kept within the Saint-Denis Temple. Constructed by the First Civilization, the artifact was capable of augmenting the Head of Saint-Denis' power to project illusions and imbue weapons with mystical power.

In August 1794, Napoleon Bonaparte employed a group of tomb raiders led by Philippe Rose to find the Temple and the artifact stored within. Arno Dorian was able to open the temple ahead of the raiders and retrieved the Head of Saint-Denis, using it to make his escape from the Temple.

Unwilling to let the artifact fall into Napoleon's hands, Arno removed the Piece of Eden from the lantern and handed it to a member of the Assassins, telling him to bring the artifact to Al Mualim in Cairo. In 1798, Napoleon led an expedition to Egypt with the intention of acquiring the Piece of Eden.

Reference

 * Assassin's Creed: Unity – Dead Kings