Columbia subject headings:
Architecture, Medieval--Italy--Siena (Province)
Castles--Italy--Siena (Province)
Siena (Italy : Province)--Description and travel.
Harvard subject headings:
Architecture, Medieval--Italy--Siena (Province)
Castles--Italy--Siena (Province)
Siena (Italy : Province)--Description and travel.
Princeton subject headings:
Architecture, Medieval--Italy--Siena (Province).
Castles--Italy--Siena (Province).
Siena (Italy : Province)--Description and travel.