Columbia subject headings:
Byzantine Empire--Foreign relations--Catholic Church.
Byzantine Empire--Foreign relations--Holy Roman Empire.
Byzantine Empire--History--1081-1453--Sources.
Diplomatics, Latin.
Diplomatics--Byzantine Empire.
Latin Empire, 1204-1261--Foreign relations.
Latin Empire, 1204-1261.
Harvard subject headings:
Byzantine Empire--Foreign relations--1081-1453--Sources.
Byzantine Empire--Foreign relations--1081-1453.
Byzantine Empire--Foreign relations--Catholic Church--Sources.
Byzantine Empire--History--Michael VIII Palaeologus, 1261-1282--Sources.
Byzantine Empire--History--Michael VIII Palaeologus, 1261-1282.
Byzantine Empire--History--Sources.
Catholic Church--Foreign relations--Byzantine Empire--Sources.
Catholic Church--Relations--Orthodox Eastern Church--History--Sources.
Diplomatics, Latin.
Diplomatics--Byzantine Empire.
Latin Empire, 1204-1261--Foreign relations.
Latin Empire, 1204-1261.
Orthodox Eastern Church--Relations--Catholic Church--History--Sources.
Princeton subject headings:
Byzantine Empire--Foreign relations--Sources.
Byzantine Empire--History--1081-1453--Sources.
Emperors--Byzantine Empire--Correspondence.