Columbia subject headings:
Byzantine Empire--History--Early works to 1800.
Crusades--Fourth, 1202-1204.
Hostory, Ancient--Early works to 1800.
Latin Empire, 1204-1261.
Harvard subject headings:
Byzantine Empire--History.
Crusades--Fourth, 1202-1204
History, Ancient--Early works to 1800
Latin Empire, 1204-1261.
Princeton subject headings: