Columbia subject headings:
Christian antiquities--Italy--Siena.
Christian art and symbolism--Italy--Siena.
Duomo di Siena.
Siena (Italy)--Antiquities.
Harvard subject headings:
Architecture, Medieval--Italy--Siena.
Christian antiquities--Italy--Siena.
Christian art and symbolism--Italy--Siena--Medieval, 500-1500.
Duomo di Siena.
Siena (Italy)--Antiquities.
Princeton subject headings:
Church buildings--Italy--Siena--Designs and plans.
Duomo di Siena.
Siena (Italy)--Buildings, structures, etc.