Guillaume de Nogaret

Guillaume de Nogaret (1265 – 11 avril 1313) was a French jurist who became the councillor and keeper of the seal to Philip IV of France. The Mentor of the French Brotherhood of Assassins, De Nogaret was the architect of the downfall of the Official Templar Order in 1307.

His wish to destroy the Templar Order finally came into fruition, when pope Benedict XI, his personnal rival, died poisoned and was replaced by Assassin-aligned Clement V and when he succeeded to turn King Philip against the Templars.

Reference

 * Assassin's Creed: Unity