Columbia subject headings:
Christianity--Essence, genius, nature--Congresses.
Christianity--Europe--History--Congresses.
Church history--Congresses.
Harvard subject headings:
Christianity--Essence, genius, nature--Congresses.
Christianity--Europe--History--Congresses.
Church history--Congresses.
Princeton subject headings:
Christianity--Essence, genius, nature--Congresses.
Christianity--Europe--History--Congresses.
Church history--Congresses.