Career
Arnaud was prior of the abbey of Cassan, bishop of Béziers (1095/6) and Archbishop of Narbonne (16 April 1121) and a papal legate. During the minority of the viscountess Ermengarde of Narbonne from 1134, Arnaud encouraged the regency of Alphonse I of Toulouse, who invaded Narbonne in 1139 with the support of the Archbishop, whom he made governor of Narbonne.