Perhaps the most noted and infamous of all the Medieval Gnostic religions, the Cathars have provided the most extensive theology. Sadly, many reports credit the Cathars for the reason of the Inquisition. The Cathars appeared in the Languedoc region of France in the 11th century, and reached their pinnacle in the 12th and 13th centuries. Scholars today believe that the Cathars likely rooted their theology in the Paulician Movement. Similar to the other Medieval Gnostic sects, the Cathars were heavily influenced by the Manichaean belief system.