Columbia subject headings:
Christianity and other religions--Islam--Congresses.
Christianity and other religions--Roman--Congresses.
Church history--Primitive and early church, ca. 30-600--Congresses.
Rome--Religion--Congresses.
Harvard subject headings:
Christian life--Rome--History--Congresses.
Christianity and other religions--Islam--Congresses
Christianity and other religions--Roman--Congresses.
Church history--Primitive and early church, ca. 30-600--Congresses.
Rome--Religion--Congresses.
Princeton subject headings:
Christian life--Rome--History--Congresses.