Columbia subject headings:
Byzantine Empire--Foreign relations--Italy.
Catholic Church--Foreign relations--Byzantine Empire.
Catholic Church--Relations--Orthodox Eastern Church.
Church history--11th century.
Italy, Southern--Church history.
Leo IX, Pope, 1002-1054.
Synod of Siponto (1050)
Harvard subject headings:
Leo IX, pope, 1002-1054.
Princeton subject headings:
Byzantine Empire--Foreign relations--Italy.
Catholic Church--Foreign relations--Byzantine Empire.
Catholic Church--Relations--Orthodox Eastern Church.
Church history--11th century.
Italy, Southern--Church history.
Leo IX, Pope, 1002-1054.
Sinod of Siponto (1050)