Columbia subject headings:
Harvard subject headings:
Constantinople (Ecumenical patriarchate)--History.
Istanbul (Turkey)--History--To 1453.
Orthodoxos Ekklēsia tēs Hellados--Turkey--History.
Patriarchs and patriarchate--Turkey--Istanbul.
Patriarchs and patriarchate.
Princeton subject headings:
Church and state--Turkey--Orthodox Eastern Church--History.
Constantinople (Ecumenical patriarchate)--History.
Greeks--Turkey--History.
Orthodox Eastern Church--Turkey--History.