Columbia subject headings:
Becker, Alfons.
Church and state--Catholic Church.
Church and state.
Church history--Middle Ages, 600-1500.
Middle Ages.
Papacy--History--To 1309.
Harvard subject headings:
Middle Ages.
Princeton subject headings:
Becker, Alfons.
Church and state--Catholic Church.
Church history--Middle Ages, 600-1500.
Middle Ages.
Papacy--History--To 1309.