Columbia subject headings:
Harvard subject headings:
Constantinople (Ecumenical patriarchate)
Councils and synods (Canon law)--Eastern churches.
Councils and synods (Canon law)--Orthodox Eastern Church
Orthodox Eastern Church--Government.
Patriarchs and patriarchate--History.
Princeton subject headings:
Constantinople (Ecumenical patriarchate)--History--Sources.
Councils and synods, Ecumenical--History.
Orthodox Eastern Church--Doctrines--History.