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The word Cathars has the same etymology as catharsis, derived from the Greek katharos, "pure". The Cathars were a gnostic Christian sect that arose in the 11th century, an offshoot of a small surviving European gnostic community that emigrated to the Albigensian region in the south of France. They deemed themselves "pure", taking vows of chastity, poverty and non-violence.
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By the early 13th century, Catharism was the majority religion in the area, supported by the nobility as well as the common people. Naturally, the Roman Catholic Church could not tolerate the existence of this sect although accounts differ on whether it considered the Cathars to be Christian heretics or simply not Christians at all. The ironically named Pope Innocent III called a formal Crusade against the Cathars. There followed over forty years of war against the indigenous population.
During this period some 500,000 Languedoc men women and children were massacred; the Counts of Toulouse and their vassels were dispossessed and humiliated, their lands annexed to France. Educated and tolerant Languedoc rulers were replaced by relative barbarians; the Dominican Order was founded and the Inquisition was established to wipe out the last vestiges of resistance; persecutions of Languedoc Jews and other minorities were initiated; the high culture of the Troubadours was lost; lay learning was discouraged; tithes were enforced; the Languedoc started its economic decline, and the language of the area, Occitan, started its descent from one of the foremost languages in Europe to a regional dialect.
At the end of the extirpation of the Cathars, the Church had convincing proof that a sustained campaign of genocide can work. It also had the precedent of an internal Crusade within Christendom, and the machinery of the first modern police state. This crusade was one of the greatest disasters ever to befall Europe. Catharism is often said to have been completely eradicated by the end of the fourteenth century. Yet there are more than a few vestiges even today, apart from the enduring memory of their martydom and the ruins of the famous "Cathar castles" like Montségur, pictured above.