Columbia subject headings:
Harvard subject headings:
Byzantine Empire--History--Constantine XI Dragases, 1448-1453.
Constantine XI, Dragases, Emperor of the East, -1453.
Istanbul (Turkey)--History--Siege, 1453.
Princeton subject headings:
Byzantine Empire--History--Constantine XI Dragases, 1448-1453.
Constantine XI Palaeologus, Emperor of the East, 1405-1453.
Istanbul (Turkey)--History--Siege, 1453.