 Pope Innocent III, organiser of the Albigensian Crusade, had granted the title Duke of Narbonne, which had been held by Aimery's uncle and namesake Aimerico Manrique until 1177, to the archbishop.Arnaud was thus Aimery's suzerain by 1212.After the Battle of Muret in 1213, Aimery refused entry in Narbonne to Simon de Montfort, who proceeded to besiege the place.