Columbia subject headings:
Harvard subject headings:
Castles--Greece--Macedonia.
Castles--Greece--Thrace, Western.
Fortification--Greece--Macedonia.
Fortification--Greece--Thrace, Western.
Macedonia (Greece)--Antiquities.
Thrace, Western (Greece)--Antiquities.
Princeton subject headings:
Fortification--Byzantine Empire.
Macedonia (Greece)--Antiquities, Byzantine.
Military architecture--Byzantine Empire.
Thrace, Western (Greece)--Antiquities, Byzantine.