Columbia subject headings:
Byzantine Empire--History--Angeli, 1185-1204.
Byzantine Empire--History--Comneni dynasty, 1081-1185.
Crusades--Fourth, 1202-1204.
Harvard subject headings:
Byzantine Empire--History--Angeli, 1185-1204.
Byzantine Empire--History--Comneni dynasty, 1081-1185.
Crusades--Fourth, 1202-1204
Princeton subject headings:
Byzantine Empire--History--Angeli, 1185-1204.
Byzantine Empire--History--Comneni dynasty, 1081-1185.
Crusades--Fourth, 1202-1204.