Master of the Hospitallers (1242-1258).
Originally from France, William of Châteauneuf had joined the order in Outremer by 1233, when he witnessed the agreement between the Hospitallers, the Templars, and the citizens of Marseilles concerning the military orders’ rights in the port of Marseilles. He became marshal of the central convent (1241) and was elected master after the death of Peter of Vieillebride (1242).
William was captured at the battle of Forbie (17 October 1244) and spent the following six years in an Egyptian prison, with John of Ronay serving as vice master in the interim until King Louis IX of France procured his release in 1250, paying a notable ransom. William admitted the priors and brethren of St. James in Acre (mod. ‘Akko, Israel) into the Hospitallers’ confraternity (1253/1254), and during his mastership the building activities in the order’s compound in Acre continued. In 1255 substantial portions of the archdiocese of Nazareth came under the administration of the Hospitallers.
William also reached important agreements concerning disputed rights and possessions with John of Ibelin and Bohemund VI of Antioch-Tripoli (1256/1257). He died in 1258 during the final phase of the War of St. Sabas and was succeeded by Hugh Revel, whose career he had supported since 1250.