Columbia subject headings:
Harvard subject headings:
Bishops--Homes and haunts--Germany--Cologne--History--To 1500.
Cologne (Germany)--Buildings, structures, etc.
Cologne (Germany)--History
Princeton subject headings:
Bishops--Homes and haunts--Germany--Cologne--History--To 1500.
Cologne (Germany)--Buildings, structures, etc.
Cologne (Germany)--History.