Columbia subject headings:
Harvard subject headings:
Christian education--History--Early church, ca. 30-600--Congresses.
Church history--Primitive and early church, ca. 30-600--Congresses
Mathematics--Religious aspects--Congresses.
Symbolism of numbers--Congresses.
Princeton subject headings:
Cardinal numbers--Religious aspects--Congresses.
Numbers in the Bible--Congresses.
Religious education--Congresses.
Symbolism of numbers--Religious aspects--Congresses.