The Cathars were an 11th-13th AD century Gnostic Christian sect that flourished in the Languedoc region of France. Cathar theology was influenced by the Bogomils and, to an extent, the teachings of the prophet Mani. In the Languedoc, famous at the time for its high culture, tolerance and liberalism, the Cathar religion took root and gained more adherents during the twelfth century until annihilated under King Philip II with the approval and encouragement of the Papacy.
The Cathars believed in two principles--a good creator god and his evil adversary. They practiced lives of simplicity and chastity. Believing the physical world to be inferior to the spiritual, the avoidance of sex was intended to keep more spirit beings from becoming entrapped in physical bodies. The Cathars were said to have committed ritual suicide, presumably as a release from the burdens of a carnal existence, but the claim of Cathar suicide has been described by some historians as mere propaganda.
The Catholic Church called them Albigenses (from the name of the city of Albi in southern France) or, less frequently, Cathars. The military campaign waged against them is often called "The Albigensian Crusade."