Columbia subject headings:
Catholic Church--Foreign relations.
Church history--8th century.
Church history--9th century.
Papacy--History--To 1309.
Harvard subject headings:
Franks--History--To 768
Lombards--History.
Papacy--History--To 1309
Princeton subject headings:
Catholic Church--Foreign relations.
Church history--8th century.
Church history--9th century.
Papacy--History--To 1309.