Excerpts from Books and Wikipedia
"The pope had long urged action against Languedoc's heretics, known as 'Cathars' or 'Albigensians.' They believed the world was created by a Satan-like entity, practiced vegetarianism, and believed in reincarnation. Although they considered themselves to be Christians, they did not recognize the Church, which had been unable to assert its authority in the Languedoc region. . . . On March 10, the pope called on the French nobility to launch a crusade against the Cathars and the count of Toulouse. The path was open for those branded as heretics to be massacred and the resulting absorption of Languedoc into the kingdom of France." [1001 Days]