Columbia subject headings:
Christian sociology--History--Middle Ages, 600-1500.
Church and state--Europe--History.
Church history--Middle Ages, 600-1500.
Papacy--History--To 1309.
Harvard subject headings:
Christian sociology--History--Middle Ages, 600-1500.
Church and state--Europe--History
Church history--Middle Ages, 600-1500
Papacy--History--To 1309
Princeton subject headings:
Christian sociology--History--Middle Ages, 600-1500.
Church and state--Europe--History.
Church history--Middle Ages, 600-1500.
Papacy--History--To 1309.