Columbia subject headings:
Harvard subject headings:
Byzantine Empire--History.
Greeks--Turkey--Trabzon--History.
Trabzon (Turkey)--History.
Trebizond Empire--History.
Turkey--History--To 1453.
Princeton subject headings:
Byzantine Empire--History.
Greeks--Turkey--Trabzon--History.
Trabzon (Turkey)--History.
Trebizond Empire--History.
Turkey--History--To 1453.