Columbia subject headings:
Basilica di San Pietro in Vaticano. Capitolo--History--Sources.
Catholic Church--Italy--Rome--History--Sources.
Chapters, Cathedral, collegiate, etc.--Vatican City--History.
Harvard subject headings:
Basilica di San Pietro in Vaticano. Capitolo--History.
Chapters, Cathedral, collegiate, etc.--Vatican City--History.
Italy--Church history--476-1400.
Princeton subject headings: