Guillaume de Nogaret (1265 – 11 April 1313) was a French jurist who became the councillor and keeper of the seal to King Philip IV of France, and one of the Mentors of the French Brotherhood of Assassins.
De Nogaret was the mastermind behind the fall of the Templar Order in 1307. His plans came into fruition after fatally poisoning Pope Benedict XI, his personal rival, who had excommunicated him. He was replaced by Clement V, who unknowingly served the Assassins. De Nogaret also managed to convince King Philip to brand the Templars as heretics and arrest their Grand Master, Jacques de Molay
Along with William of Paris and Philippe de Marigny, de Nogaret tortured de Molay and forced a confession to heresy out of him. The Templar and several of his closest men were subsequently burned at the stake, which marked the public disbanding of the Order, driving the Templars into becoming a clandestine organization, operating in secrecy.
During the French Revolution, de Nogaret's descendant, Paul Teragon, used a reversible anagram of the family name to hide his identity from those who would potentially seek vengeance for the Templars against his family. When his friend, Bertrand Grimany, a descendant of Marigny also using a false name, revealed his own ancestry to a Parisian newspaper, both he and Teragon were murdered by Anne de Molay, a descendant of Jacques de Molay.