Calling themselves "Good Christians" and centered in the Languedoc Region of France during the 12th and 13th centuries, the Cathars were considered a heretical sect by the Catholic Church. Although heresy had been suppressed for centuries by the church, the Cathars grew so quickly that the church launched the Albigensian Crusade to eliminate them and soon afterwards implemented the Inquisition in order to quell similar movements. The Cathars religious beliefs are partially shrouded in mystery and are a subject of intense debate, but one thing is for sure: they believed that the Catholic Church was corrupt and they openly challenged many of its core practices.

Formation

The Cathars, who were better known as the Albigensians in their day, practiced a form of Christianity that was closely related to the communal living forms of early Christians, as depicted in the book of Acts (4:32–35). They were also influenced by Eastern Christian practices and movements, most notably the Bogomils of Bulgaria - who also advocated a return to a early Christian form of living. These movements, including the Cathars, formed as a reaction to the Catholic church's consolidation of power during the crusades and may have been influenced by other earlier movements such as Gnostism, which still survived to some degree in the Arab world.

Dualism

The defining belief attributed to the Cathars by many sources, and especially their persecutors, is that of "dualism". Dualism sees the world as divided into two primary principles, good and evil, and attributes evil characteristics to all things material while believing that good resides only on the spiritual plane. Cathars strove to become "Perfect" - the name given to their priests and devout practitioners - by renouncing all worldly things and becoming pure. These beliefs also had a historical context dating back to the Manchaean movement of the 3rd century AD, a dualistic movement that influenced much of Eastern Europe (and had possibly even older roots).

Moral Beliefs

The Cathars were vegetarians who did not worship in a church but instead prefered to hold their ceremonies outside. They did not use idols or instruments and even rejected the cross as a symbol of Jesus Christ. They were non-materialistic and may have shared property and wealth. War and capital punishment were rejected by the Cathars and vows and oaths were not important, including marriage vows. Male and female were treated equally and sex for procreation was seen as morally evil since it purposely brought another soul into the material (and therefore degenerate) world. Contraception however, was widely accepted.

Political Beliefs

Strictly non-hierarchal and egalitarian, what got the Cathars in so much trouble were their revolutionary political ideas. They openly rejected the rule of both the Catholic Church and the French State. Beyond this, the Cathars accused the Catholic Church of outright corruption and denounced the practices of selling indulgences, wearing fine clothes, taking the communion and even baptism, alleging that they were all empty materialistic rituals. The fact that these ideas, and the Cathar movement in general, was spreading like wildfire brought down a bloody 20-year military crusade upon their heads and lead directly to the wide and forceful suppression of all church dissenters called the Medieval Inquisition.