Guy was the sixth Cistercian abbot of Vaux-de-Cernay from 1181 until 1210 and then the bishop of Carcassonne from 1212 until his death. The crusades dominated his life. He was a preacher, organizer and spiritual leader of the Fourth Crusade, which he abandoned after it turned against fellow Catholics, and also of the Albigensian Crusade against heretics.

Vaux-de-Cernay Abbey is a former Cistercian monastery in northern France (Île-de-France), situated in Cernay-la-Ville, in the Diocese of Versailles, Yvelines. The abbey was abandoned during the French Revolution and fell into partial ruin. Most of the buildings, except for the church, were restored in the late 19th century by Charlotte de Rothschild, and the property is now a hotel.