Columbia subject headings:
Harvard subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Dvornik, Francis, 1893-1975. Photian schism.
Orthodox Eastern Church--Relations--Catholic Church.
Photius I, Saint, Patriarch of Constantinople, approximately 820-approximately 891.
Schism--Eastern and Western Church.
Princeton subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Dvornik, Francis, 1893-1975. Photian schism.
Orthodox Eastern Church--Relations--Catholic Church.
Photius I, Saint, Patriarch of Constantinople, approximately 820-approximately 891.
Schism--Eastern and Western Church.