Columbia subject headings:
Castles--Germany--Mönchengladbach--History.
Fortification--Germany--Mönchengladbach--History.
Fortress-churches--Germany--Mönchengladbach--History.
Mönchengladbach (Germany)--Defenses--History.
Mönchengladbach (Germany)--History.
Thirty Years' War, 1618-1648.
Harvard subject headings:
Castles--Germany--Mönchengladbach--History.
Fortification--Germany--Mönchengladbach--History.
Fortress-churches--Germany--Mönchengladbach--History.
Mönchengladbach (Germany)--Defenses--History.
Mönchengladbach (Germany)--History.
Thirty Years' War, 1618-1648
Princeton subject headings: