Columbia subject headings:
Christian union--History.
Church history--Modern period, 1500-
Ecumenical movement--History.
Harvard subject headings:
Christian union--History.
Church history--Modern period, 1500-
Ecumenical movement--History.
Ecumenical movement.
Princeton subject headings:
Christian union--History.
Church history--Modern period, 1500-
Ecumenical movement--History.