The Head of Saint Denis was an ancient head-shaped lantern, which encased an Apple of Eden. Following the Apple's removal, the Head of Saint Denis became a regular, but self-illuminating lantern, requiring no fuel.
The Head of Saint Denis was a lantern which was used in the 12th century by the Abbot Suger of Saint Denis. He used the knowledge attained from the Apple of Eden wired within the Lantern to create the Eagle of Suger – a powerful sword – and hid the Head of Saint Denis inside a First Civilization temple located in Saint-Denis, beneath the Basilica of Saint-Denis.
In August 1794, Arno Dorian battled a group of tomb raiders sent by Napoleon Bonaparte in order to find the artifact in the First Civilization Temple hidden beneath the Basilica of Saint-Denis. The Assassin killed their leader, Philippe Rose, and used the power of the Apple contained within the lantern to repel the remaining raiders.
Realizing the dangers of the lantern's power should it fall into Napoleon's hands, Arno removed the Apple stored within and contacted the members of the French Assassin Brotherhood, asking them to send the Apple to Al Mualim in Cairo. Upon delivering the artifact to its escort, Arno kept the relic, the Head of Saint Denis itself, as a memento.
By 1868, the lantern had been obtained by the British Rite of the Templar Order, and was kept by David Brewster inside his laboratory. It was destroyed alongside the laboratory when the device he used to experiment on an Apple of Eden malfunctioned, causing the Piece of Eden to detonate.
Without the power of the Apple of Eden, The Head of Saint Denis is a regular, but self-laminating lantern which requires no form of fuel to burn. Even dipping it in water will not damage or reduce its effects.
When the Head of Saint Denis is fueled by the Apple of Eden's power, the artifact emitted a shimmering blue light and had possessed the power to conjure up terrifying illusions which would scare people to the point where they would die from heart failure caused by the intense fear. It can even imbue weapons with a mystical power.