Catharism (/ˈkæθərɪzəm/; from the Greek: καθαροί, katharoi, "the pure [ones]") was a Christian dualist movement that thrived in some areas of Southern Europe, particularly northern Italy and southern France, between the 12th and 14th centuries. Cathar beliefs varied between communities because Catharism was initially taught by ascetic priests who had set few guidelines.