Columbia subject headings:
Catholic Church--Foreign relations--Germany.
Catholic Church--Germany--Cologne--History--Sources.
Germany--Foreign relations--Catholic Church.
Harvard subject headings:
Archivio vaticano--Catalogs.
Catholic Church--Foreign relations--Germany.
Catholic Church--Germany--Cologne--History--Sources.
Germany--Foreign relations--Catholic Church.
Papal nuncios--Germany--Cologne--History--Sources.
Princeton subject headings:
Catholic Church--Foreign relations--Germany.
Catholic Church--Germany--Cologne--History--Sources.
Germany--Foreign relations--Catholic Church.