Innocent III, upon ascending the papal throne in 1198, had at first tried pacific conversion of the Cathar heretics of southern France, who have long denied the sacraments and the authority of the ecclesiastical hierarchy.
In 1207, he appoints Pierre de Castelnau, a prominent Cistercian, as apostolic legate and inquisitor to lead an expedition against the Cathari (better known as Albigenses after the town of Albi) and particularly to obtain the recantation of Count Raymond VI de Toulouse, who is allowing the heresy to spread throughout his domain.
A nephew of King Louis VII of France and brother-in-law of King Richard I of England, Raymond is tolerant toward the many heretics among his subjects.
Apparently, although the Cathari reject Judaism on theological grounds, many also reject the notion of Jesus as a god and accuse the Church of social and economical corruption.
Jews fare well in areas under their control, even attaining positions of prominence.
Having urged him from 1205 to stamp out the heretics, Peter now excommunicates Raymond, placing the Languedoc region under interdict, which arouses grave opposition.