Albigensian Crusade

The Albigensian Crusade was a twenty-year military campaign called by Pope Innocent III in 1209 to eliminate the Cathar heresy centered in the Languedoc region of southern France, named for the town of Albi associated with the movement. Crusading forces from northern France, led initially by Simon de Montfort, seized Cathar-sympathizing towns including Beziers, where the sack of the city and the massacre of its population gave rise to the order later attributed, possibly apocryphally, to the papal legate Arnaud Amalric to kill them all and let God know his own. The war combined religious suppression with the political ambitions of the French crown, which used the crusade to extend royal authority into the previously semi-independent county of Toulouse, and after Simon de Montfort's death in 1218 the conflict continued under royal leadership until the Treaty of Paris in 1229 brought Languedoc under direct French crown control. The subsequent Medieval Inquisition, established substantially to complete the Cathars' suppression, extinguished the movement over the following decades.