Columbia subject headings:
Harvard subject headings:
Church history--Primitive and early church, ca. 30-600--Congresses.
Constantine I, Emperor of Rome, -337--Congresses.
Rome--History--Constantine I, the Great, 306-337--Congresses.
Princeton subject headings:
Church and state--Rome--History--Congresses.
Church history--4th century--Congresses.
Constantine I, Emperor of Rome, -337--Congresses.
Rome--History--Constantine I, the Great, 306-337--Congresses.