Columbia subject headings:
Istanbul (Turkey)--History--Siege, 1453--Congresses.
Mehmed II, Sultan of the Turks, 1432-1481--Congresses.
Harvard subject headings:
Istanbul (Turkey)--History--Siege, 1453--Congresses.
Mehmed II, Sultan of the Turks, 1432-1481--Congresses.
Princeton subject headings:
Mehmed II, Sultan of the Turks, 1432-1481--Congresses.