The Vatican necropolis lies beneath Vatican City, specifically beneath the present St. Peter's Basilica, at depths ranging from 5 to 12 meters. The necropolis was partially exposed by means of archaeological excavations in 1940-1949. The necropolis was an open-air burial ground that included both mausolea and tombs. Notable among the documented tombs are the Tomb of the Iulii and the tomb that is conventionally believed to be that of Saint Peter (a.k.a. Peter the Apostle). The tomb of the saint, said to be located near the site of his martyrdom, provides a point of topographic orientation for the Constantinian project that came to be Old St. Peter's. The necropolis remained in use until at least 318.
Jeffrey Becker,
'Vatican necropolis: a Pleiades place resource',
Pleiades: A Gazetteer of Past Places,2024
<https://pleiades.stoa.org/places/975276180> [accessed: 23 November 2024]
{{cite web |url=https://pleiades.stoa.org/places/975276180 |title=Places: 975276180 (Vatican necropolis) |author=Becker, J. |accessdate=November 23, 2024 11:21 pm |publisher=Pleiades}}