Columbia subject headings:
Castles--Mediterranean Region.
Cities and towns, Medieval--Mediterranean Region.
Fortification--Mediterranean Region.
Mediterranean Region--History.
Harvard subject headings:
Fortification--Mediterranean Region--History--To 1500--Congresses.
Mediterranean Region--Antiquities--Congresses.
Mediterranean Region--History--476-1517--Congresses.
Princeton subject headings:
Castles--Mediterranean region.
Cities and towns, Medieval--Mediterranean region.
Fortification--Mediterranean region.
Mediterranean Region--History.