Columbia subject headings:
Gates--Italy--Rome--History.
Porta Maggiore (Rome, Italy)--History.
Rome (Italy)--Buildings, structures, etc.--History.
Harvard subject headings:
Gates--Italy--Rome--History.
Gates--Italy--Rome.
Porta Maggiore (Rome, Italy)
Porta Maggiore (Rome, Italy)--History.
Rome (Italy)--Antiquities.
Rome (Italy)--Buildings, structures, etc.--History.
Princeton subject headings:
Gates--Italy--Rome--History.
Porta Maggiore (Rome, Italy)--History.
Rome (Italy)--Buildings, structures, etc.--History.