Columbia subject headings:
Christian heresies--History--Middle Ages, 600-1500.
Church history--Middle Ages, 600-1500.
Papacy.
Sects, Medieval.
Harvard subject headings:
Church history--Middle Ages, 600-1500
Papacy--History
Sects, Medieval.
Princeton subject headings:
Church history--Middle Ages.
Papacy--History.
Sects, Medieval.