Columbia subject headings:
Architecture, Medieval--Vatican City.
Nicholas III, Pope, -1280.
Vatican City--Buildings, structures, etc.
Vatican City--History.
Vatican Palace (Vatican City)--History.
Harvard subject headings:
Architecture, Medieval--Vatican City.
Interior decoration--Vatican City.
Palaces--Vatican City.
Vatican City--Buildings, structures, etc.
Vatican Palace (Vatican City)--History.
Princeton subject headings:
Vatican City--Buildings, structures, etc.
Vatican Palace (Vatican City)--History.