Columbia subject headings:
Councils and synods.
Harvard subject headings:
Church history--Middle Ages, 600-1500
Church history--Primitive and early church, ca. 30-600
Councils and synods, Ecumenical--History.
Councils and synods.
Princeton subject headings:
Church history--Middle Ages, 600-1500.
Church history--Primitive and early church, ca. 30-600.
Councils and synods, Ecumenical--History.