Columbia subject headings:
Christian life--History--Early church, ca. 30-600--Congresses.
Christian life--History--Middle Ages, 600-1500--Congresses.
Church history--Middle Ages, 600-1500--Congresses.
Greece--Religious life and customs--Congresses.
Religion and sociology--Congresses.
Religion--Congresses.
Rome--Religious life and customs--Congresses.
Harvard subject headings:
Christian life--History--Early church, ca. 30-600--Congresses.
Christian life--History--Middle Ages, 600-1500--Congresses.
Church history--Middle Ages, 600-1500--Congresses.
Greece--Religious life and customs--Congresses.
Rome--Religious life and customs--Congresses.
Princeton subject headings:
Christian life--History--Early church, ca. 30-600--Congresses.
Christian life--History--Middle Ages, 600-1500--Congresses.
Church history--Middle Ages, 600-1500--Congresses.
Greece--Religious life and customs--Congresses.
Religion and sociology--Congresses.
Religion--Congresses.
Rome--Religious life and customs--Congresses.