Columbia subject headings:
Harvard subject headings:
Byzantine Empire--Foreign relations.
Byzantine Empire--History--1081-1453.
Byzantine Empire--History--527-1081.
Diplomacy--History--To 1500.
Diplomatic and consular service--Byzantine Empire--History--To 1500.
Diplomats--History--To 1500.
Princeton subject headings:
Ambassadors--Byzantine Empire.
Byzantine Empire--Foreign relations--1081-1453.
Byzantine Empire--Foreign relations--527-1081.