Columbia subject headings:
Canon law--History.
Church history--Middle Ages, 600-1500.
Holy Roman Empire--Church history.
Papacy--History.
Zimmermann, Harald, 1926-
Harvard subject headings:
Church history--Middle Ages, 600-1500
Europe--History--476-1492.
Middle Ages.
Princeton subject headings:
Church history--Middle Ages, 600-1500.
Europe--History--476-1492.
Middle Ages.