Columbia subject headings:
Castles in literature--Congresses.
Castles--Congresses.
Imaginary buildings in literature--Congresses.
Imaginary buildings--Congresses.
Harvard subject headings:
Castles--France--History--Congresses.
Fortification--France--History--Congresses.
France--Antiquities--Congresses.
France--Civilization--Congresses.
Princeton subject headings:
Castles--France--History--Congresses.
Fortification--France--History--Congresses.
France--Antiquities--Congresses.
France--Civilization--Congresses.