Columbia subject headings:
Harvard subject headings:
Castles--Italy--Marche--History--To 1500.
Fortification--Italy--Marche--History.
Land settlement patterns--Italy--Marche--History--To 1500.
Princeton subject headings:
Castles--Italy--Marche--History--To 1500.
Land settlement patterns--Italy--Marche--History--To 1500.