Blessed Pierre de Castelnau was born in the diocese of Montpellier. He became archdeacon of Maguelonne, and in 1199 was appointed by Pope Innocent III as one of the papal legates for the suppression of the Cathar heresy in Languedoc. In 1202, he made profession as a Cistercian monk at the abbey of Fontfroide, Narbonne, and by 1203 was confirmed as papal legate and chief inquisitor, first in Languedoc, and afterwards at Viviers and Montpellier.
In 1207, Blessed Pierre was appointed was in the Rhone valley and in Provence, where he became involved in the strife between the count of Baux and Raymond VI, Count of Toulouse. Castelnau was assassinated on 15 January 1208, possibly by an agent of Raymond, but this was never proven. Nevertheless, Pope Innocent III held Raymond responsible and Pierre’s murder was the immediate cause of Raymond’s excommunication and the start of the Albigensian Crusade.
Blessed Pierre was beatified, through papal order, in 1208 by Pope Innocent III. The relics of Pierre de Castelnau are interred in the church of the ancient Abbey of St-Gilles.
Sources:
https://www.catholic.org/saints/saint.php?saint_id=5303
Graham-Leigh, Elaine (2005). The Southern French Nobility and the Albigensian Crusade. The Boydell Press, Woodbridge.
Madaule, Jacques (1967). The Albigensian Crusade: An Historical Essay. Fordham University Press.
Oldenbourg, Zoe (2015). Massacre At Montsegur: A History Of The Albigensian Crusade. Hachette UK.
Ryan, James D. (2004). "Missionary Saints of the High Middle Ages: Martyrdom, Popular Veneration, and Canonization". The Catholic Historical Review. 90, No. 1 (Jan.): 1–28
