Catharism

The Cathar symbol

The Cathars were a heretical sect that first appeared in historical records of Europe about 1143. In truth, the term was used earlier: the first Council of Nicaea in 325 discussed allowing "Cathars" to convert to the approved Christianity, and the 8th century St. John Damascene's book on heresies mentions Cathars, but the group of which we know more in the Middle Ages was probably not related to those earlier groups.

The confusion would come from the name itself. "Cathar" comes from the Greek katharoi, meaning "the pure ones." The later medieval Cathars were a dualist movement: they believed that there were two opposing forces of equal power, good and evil. The good was represented by a single God (no Trinity for them!) and the spiritual side of life; the material world was the result of a god of evil, Satan. They therefore rejected (as much as possible) the material world., since it was all tainted with sin by its connection to Satan. One aspect of the material world that they rejected was sex and its partner, marriage, as this blog discussed here.

Groups of Cathars flourished in the 12th century in the Rhineland, France, and northern Italian cities. Their lifestyle was a radical departure from the norm, but it was not objectionable to many. Bernard of Clairvaux, one of the strongest voices in Christianity of his day) said of them:

If you question the heretic about his faith, nothing is more Christian; if about his daily converse, nothing more blameless; and what he says he proves by his actions ... As regards his life and conduct, he cheats no one, pushes ahead of no one, does violence to no one. Moreover, his cheeks are pale with fasting; he does not eat the bread of idleness; he labours with his hands and thus makes his living. Women  are leaving their husbands, men are putting aside their wives, and they all flock to those heretics! Clerics and priests, the youthful and the adult among them, are leaving their congregations and churches.... [Sermon 65]

They were ascetic Christians living the Christian life, harming no one. They rejected, however, the trappings of Roman Catholicism. Pope Innocent III tried to bring them back "into the fold" by sending missionaries to preach to them. One of these, Pierre de Castelnau, was murdered on 15 January, 1208, during one such attempt, supposedly by Count Raymond of Toulouse, whom he was accusing of being too lenient with the Cathars. After this act, Innocent abandoned his attempts to win over the Cathars, and instead decided to wipe them out with the action known as the Albigensian Crusade.