Catharism was a Christian quasi-dualist and pseudo-Gnostic movement which thrived in northern Italy and southern France between the 12th and 14th centuries. Denounced as a heretical sect by the Catholic Church, its followers were attacked first by the Albigensian Crusade and later by the Medieval Inquisition, which eradicated them by 1350. Thousands were slaughtered, hanged, or burned at the stake.