Columbia subject headings:
Catholic Church--Byzantine rite, Ruthenian--History--16th century.
Catholic Church--Poland--History--16th century.
Catholic Church--Relations--Orthodox Eastern Church.
Catholic Church. Metropolitanate of Kyïv--History.
Catholic Church. Metropolitanate of Kyïv.
Constantinople (Ecumenical patriarchate)--History.
Orthodox Eastern Church--Relations--Catholic Church.
Ukraine--Church history.
Union of Brest
Harvard subject headings:
Catholic Church--Byzantine rite, Ruthenian--History--16th century.
Catholic Church--Poland--History--16th century.
Catholic Church--Relations--Orthodox Eastern Church.
Catholic Church. Metropolitanate of Kyïv
Constantinople (Ecumenical patriarchate)--History.
Orthodox Eastern Church--Relations--Catholic Church.
Ukraine--Church history.
Union of Brest
Princeton subject headings:
Catholic Church--Byzantine rite, Ruthenian--History--16th century.
Catholic Church--Poland--History--16th century.
Catholic Church--Ukraine--History--16th century.
Catholic Church. Metropolitanate of Kyïv--History.
Constantinople (Ecumenical patriarchate)--History.
Poland--Church history.
Ukraine--Church history.
Union of Brest