Columbia subject headings:
Harvard subject headings:
Byzantine Empire--History.
Byzantine Empire--Politics and government
Constantine IV, Emperor of the East, -685.
Heraclius, Emperor of the East, approximately 575-641.
Western countries--History.
Princeton subject headings:
Byzantine Empire--History.
Byzantine Empire--Politics and government.
Constantine IV, Emperor of the East, -685.
Heraclius, Emperor of the East, approximately 575-641.
Western countries--History.