Amaury de Montfort was the third son of parliamentary pioneer Simon de Montfort, 6th Earl of Leicester, and Eleanor of England, daughter of King John.
Background
After the deaths of his father and older brother Henry de Montfort at the Battle of Evesham in 1265 (by men under the command of then Prince Edward, later Edward I, aka Edward Longshanks), Amaury fled to France with his mother, younger sister, and surviving brothers.
Career
Amaury entered the priesthood as a young man, and held the positions of Treasurer of York Cathedral, canon of Rouen, Évreux, London and Lincoln. He served as a papal chaplain as well. Amaury de Montfort soon began studying medicine and theology at the University of Padua.
Henry, whom the de Montfort sons considered a traitor to their father"s ideals, was attacked during mass at Viterbo, and murdered on the altar steps, resulting in the excommunication of both de Montfort sons.
While Amaury was not in Viterbo, and was not involved in the murder, Edward swore vengeance upon all of Simon de Montfort"s sons, Amaury included. Simon the younger died that year, reportedly of a tertian fever, while Guy managed to appeal to the pope (with the aid of his father-in-law), resulting in his return to the church.
Intercepted at sea by mercenaries in the employ of now King Edward I, both Amaury and Eleanor were taken captive. Following two paragraphs taken mainly from Chronica, ascribed to William Rishanger, a monk of Saint Albans, educated
Henry Thomas Riley, 87, 99.
While Eleanor"s captivity was gentle and relatively short-lived (she was married to Prince Llywelyn at King Edward"s expense in 1278), Amaury was held "without rigour" in Corfe Castle and later in Sherborne Castle. After requests from the Pope, Prince Llywelyn and Archbishop John Peckham of Canterbury, Amaury was released after swearing at London not to return to England unless invited by the king. Amaury after some years renounced his clerical career and became a knight, apparently dying soon afterwards in Italy, possibly after 1301(citation/reference?).