Columbia subject headings:
Castles--Greece.
Castles--Latin Orient.
Castles--Malta.
Castles--Middle East.
Fortification--Greece.
Fortification--Latin Orient.
Fortification--Malta.
Fortification--Middle East.
Hospitalers.
Harvard subject headings:
Princeton subject headings:
Fortification--Mediterranean Region.
Fortification--Middle East.
Knights of Malta--History.