Columbia subject headings:
Harvard subject headings:
Catholic Church--Relations--Orthodox Eastern Church.
Church history--Middle Ages, 600-1500
Church history--Modern period, 1500-
Church history--Primitive and early church, ca. 30-600
Orthodox Eastern Church--Relations--Catholic Church.
Princeton subject headings:
Church history--Middle Ages, 600-1500.
Church history--Modern period, 1500-
Church history--Primitive and early church, ca. 30-600.