Columbia subject headings:
Architecture, Medieval--Conservation and restoration--Italy--Lazio.
Exterior walls--Italy--Lazio--Design and construction--History.
Historic buildings--Conservation and restoration--Italy--Lazio.
Harvard subject headings:
Architecture, Medieval--Italy--Lazio.
Lazio (Italy)--Buildings, structures, etc.
Walls--Italy--Lazio--Conservation and restoration.
Walls--Italy--Lazio--Design and construction--History.
Princeton subject headings:
Building--Italy--Lazio--History.
Walls--Italy--Lazio--Design and construction--History.