Columbia subject headings:
Architecture, Medieval--Europe.
Castles--Europe.
Church buildings--Europe.
Teutonic Knights--History.
Harvard subject headings:
Architecture, Medieval--Livonia--History.
Architecture, Medieval--Mediterranean Region--History.
Architecture, Medieval--Prussia, East (Poland and Russia)--History.
Teutonic Knights--History.
Princeton subject headings:
Architecture, Medieval--Europe.
Castles--Europe.
Church buildings--Europe.
Teutonic Knights--History.