Columbia subject headings:
Castles--England--History.
Castles--Wales--History.
Fortification--England--History.
Fortification--Wales--History.
Great Britain--History--Medieval period, 1066-1485.
Wales--History--1063-1536.
Harvard subject headings:
Castles--England--History.
Castles--Wales--History.
England--Civilization--1066-1485
Fortification--England--History.
Fortification--Wales--History.
Wales--History--To 1536.
Princeton subject headings:
Castles--England--History.
Castles--Wales--History.
Fortification--England--History.
Fortification--Wales--History.
Great Britain--History--Medieval period, 1066-1485.
Wales--History--1063-1536.