Columbia subject headings:
Byzantine Empire--History--Constantine XI Dragases, 1448-1453--Sources.
Istanbul (Turkey)--History--Siege, 1453--Sources.
Harvard subject headings:
Byzantine Empire--History--Constantine XI Dragases, 1448-1453--Sources.
Istanbul (Turkey)--History--Siege, 1453--Sources.
Princeton subject headings:
Byzantine Empire--History--Constantine XI Dragases, 1448-1453--Sources.
Istanbul (Turkey)--History--Siege, 1453--Sources.