Catharism (/ˈkæθərɪzəm/; from the Ancient Greek: καθαροί, romanized: katharoi, "the pure ones") was a Christian dualist or Gnostic movement between the 12th and 14th centuries which thrived in Southern Europe, particularly in northern Italy and southern France. Followers were described as Cathars and referred to themselves as Good Christians; in modern times, they are mainly remembered for a prolonged period of religious persecution by the Catholic Church, which did not recognize their unorthodox Christianity.