Columbia subject headings:
Catholic Church--Europe--History--To 1500.
Church and state--Europe--History--To 1500.
Church history--Middle Ages, 600-1500.
Investiture--History--To 1500.
Harvard subject headings:
Catholic Church--Europe--History--To 1500.
Church and state--Europe--History--Congresses.
Europe--Church history--600-1500--Congresses.
Investiture--History--To 1500--Congresses.
Princeton subject headings:
Catholic Church--Europe--History--To 1500.
Church and state--Europe--History--To 1500.
Church history--Middle Ages, 600-1500.
Investiture--History--To 1500.