Upon the election of Otho as Emperor, in 1208, Germany and Rome were at peace, and Pope Innocent III. found himself at liberty to devote some attention to affairs in Southern France.  He had already made some efforts to oppose the growth of heresy:  his first emissaries were unable to produce the least effect and in 1208 he had sent Arnaut of Citeaux and two Cistercian monks into Southern France with full powers to act.  Their efforts proved fruitless, because Philippe Auguste was no less indifferent than the provincial lords, who actually favoured the [77] heretics in many cases; the Roman Catholic bishops also were jealous of the pope’s legates and refused to support them.  Not only the laity but many of the clergy had been seduced:  the heretics had translated large portions of scripture (translations which still remain to us) and constantly appealed to the scriptures in opposition to the canon laws and the immorality of Rome.  They had a full parochial and diocesan organisation and were in regular communication with the heretics of other countries.  It was clear that the authority of Southern France was doomed, unless some vigorous steps to assert her authority were speedily taken.  “Ita per omnes terras multiplicati sunt ut grande periculum patiatur ecclesia Dei.” [27] The efforts of St Dominic were followed by the murder of the papal legate, Pierre de Castelnau, in 1208, which created an excitement comparable with that aroused by the murder of Thomas a Becket, thirty-eight years before, and gave Innocent III. his opportunity.  In the summer of 1209 a great army of crusaders assembled at Lyons, and Southern France was invaded by a horde composed partly of religious fanatics, of men who were anxious to gain the indulgences awarded to crusaders without the danger of a journey overseas, and of men who were simply bent on plunder.  The last stage in the development of the crusade movement was thereby reached:  originally begun to recover [78] the Holy Sepulchre, it had been extended to other countries against the avowed enemies of Christianity.  Now the movement was to be turned against erring members of the Christian Church and in the terms of a metaphor much abused at that period, the Crusader was not only to destroy the wolf, but to drive the vagrant sheep back into the fold.[28] Beziers and Carcassonne were captured with massacre; Toulouse was spared upon the humiliating submission of Raimon VI., and little organised opposition was offered to the crusading forces under Simon de Montfort.  The following years saw the revolt of Toulouse and the excommunication of Raimon VI. (1211), the battle of Muret in which Raimon was defeated and his supporter Pedro of Aragon, was killed (1213), the Lateran Council (1215), the siege of Toulouse and the death of Simon de Montfort (1218).  The foundation of the Dominican order and of the Inquisition marked the close of the struggle.