Columbia subject headings:
Castles--Europe--History--To 1500.
Fortification--Europe--History--To 1500.
Land settlement patterns--Europe--History.
Harvard subject headings:
Castles--Europe, Western--History--To 1500.
Europe--History--476-1492--Historiography.
Feudalism--Europe, Western.
Land settlement patterns--Europe, Western--History--To 1500.
Social history--Medieval, 500-1500--Historiography.
Princeton subject headings:
Castles--Europe--History--To 1500.
Fortification--Europe--History--To 1500.
Land settlement patterns--Europe--History.