Columbia subject headings:
Byzantine Empire--Foreign relations--Catholic Church.
Catholic Church--Foreign relations--Byzantine Empire.
Catholic Church--History.
Merovingians.
Papal States--History--Sources.
Papal States--History.
Harvard subject headings:
Byzantine Empire--Foreign relations--Catholic Church.
Catholic Church--Foreign relations--Byzantine Empire.
Catholic Church--History.
Merovingians.
Papal States--History--Sources.
Papal States--History.
Princeton subject headings: