Columbia subject headings:
Byzantine Empire--Civilization--Congresses.
Byzantine Empire--Foreign relations--1081-1453--Congresses.
Latin Empire, 1204-1261--Foreign relations--Congresses.
Harvard subject headings:
Byzantine Empire--Civilization--Congresses.
Byzantine Empire--Foreign relations--1081-1453--Congresses.
Latin Empire, 1204-1261--Foreign relations--Congresses.
Princeton subject headings:
Byzantine Empire--Civilization--Congresses.
Byzantine Empire--Foreign relations--1081-1453--Congresses.
Latin Empire, 1204-1261--Foreign relations--Congresses.