<P> The Cathars spent much of 1209 fending off the crusaders . The Béziers army attempted a sortie but was quickly defeated, then pursued by the crusaders back through the gates and into the city . Arnaud - Amaury, the Cistercian abbot - commander, is supposed to have been asked how to tell Cathars from Catholics . His reply, recalled by Caesarius of Heisterbach, a fellow Cistercian, thirty years later was "Caedite eos . Novit enim Dominus qui sunt eius"--"Kill them all, the Lord will recognise His own". The doors of the church of St Mary Magdalene were broken down and the refugees dragged out and slaughtered . Reportedly at least 7,000 innocent men, women and children were killed there by Catholic forces . </P> <P> Elsewhere in the town, many more thousands were mutilated and killed . Prisoners were blinded, dragged behind horses, and used for target practice . What remained of the city was razed by fire . Arnaud - Amaury wrote to Pope Innocent III, "Today your Holiness, twenty thousand heretics were put to the sword, regardless of rank, age, or sex ." "The permanent population of Béziers at that time was then probably no more than 5,000, but local refugees seeking shelter within the city walls could conceivably have increased the number to 20,000 ." </P> <P> After the success of his siege of Carcassonne, which followed the Massacre at Béziers in 1209, Simon de Montfort was designated as leader of the Crusader army . Prominent opponents of the Crusaders were Raymond Roger Trencavel, viscount of Carcassonne, and his feudal overlord Peter II, the king of Aragon, who held fiefdoms and had a number of vassals in the region . Peter died fighting against the crusade on 12 September 1213 at the Battle of Muret . Simon de Montfort was killed on 25 June 1218 after maintaining a siege of Toulouse for nine months . </P> <P> The official war ended in the Treaty of Paris (1229), by which the king of France dispossessed the house of Toulouse of the greater part of its fiefs, and that of the Trencavels (Viscounts of Béziers and Carcassonne) of the whole of their fiefs . The independence of the princes of the Languedoc was at an end . But in spite of the wholesale massacre of Cathars during the war, Catharism was not yet extinguished and Catholic forces would continue to pursue Cathars . </P>

Who were the cathars and what did they do