Catharism ( / ˈkæθərɪzəm /; from the Ancient Greek: καθαροί, romanized : katharoi, "the pure ones" [1] - καθαροί.)

The Cathars were adherents of a Christian sect known as Catharism that emerged in the Languedoc region of southern France during the 12th and 13th centuries. Catharism was a dualistic and Gnostic movement, emphasizing the dichotomy between the material and spiritual realms, with the latter being associated with good and the former with evil. Cathars sought spiritual purity and renounced the authority of the Catholic Church.

Their beliefs challenged the Catholic Church's power, leading to their persecution. In response, the Catholic Church initiated the Albigensian Crusade, a brutal campaign against the Cathars, and established the Inquisition to suppress them. This led to the decline of Catharism and their eventual eradication. Despite their extinction, the Cathars left a lasting imprint on the history of heretical movements and continue to be subjects of historical fascination and cultural interest.