Catharism was a religious movement that emerged in the 12th century in southern France. It was characterized by dualistic beliefs, viewing the material world as evil and the spiritual realm as good. Cathars rejected the authority of the Roman Catholic Church and promoted a simple lifestyle, emphasizing personal spiritual experience over institutional rituals. The Cathars believed in two opposing forces: a good god who created the spiritual world and an evil god responsible for the material world. Their teachings attracted many followers, leading to conflicts with the Catholic Church, culminating in the Albigensian Crusade in the early 13th century aimed at eradicating Cathar beliefs.