Columbia subject headings:
Byzantine Empire--History.
Emperors--Byzantine Empire--Titles.
Emperors--Rome--Titles.
Rome--History.
Titles of honor and nobility--Byzantine Empire--History.
Titles of honor and nobility--Rome--History.
Harvard subject headings:
Emperors--Byzantine Empire
Emperors--Rome
Titles of honor and nobility--Byzantine Empire.
Titles of honor and nobility--Rome.
Princeton subject headings:
Emperors--Byzantine Empire--Titles.
Emperors--Rome--Titles.