The Vatican sponsored archaeological excavations (also known by their Italian name scavi) under Saint Peter's in the years 1940–1949 which revealed parts of a necropolis dating to the Roman Empire.

[1] The work was undertaken at the request of Pope Pius XI who wished to be buried as close as possible to Peter the Apostle.

The obelisk had been there since ancient times; in 1586 it was moved from its original place by Domenico Fontana on the orders of Pope Sixtus V when St. Peter's Square was added.

[3] The original location was just in front of the present-day Excavation Office (Ufficio Scavi) of the Fabbrica di San Pietro and is marked by a plaque in the ground.

To obtain the necessary amount of flat area for the planned construction, Emperor Constantine I excavated part of the necropolis of the Vatican hill.

[5] This caused the necropolis to be filled with soil and building debris, with the exception of St. Peter's tomb, which was preserved.

The mausoleums were initially labeled with the Greek alphabet letters Φ (phi), Χ (chi) and Ψ (Psi).

This large number is due to the high infant mortality and low life expectancy in the 2nd Century CE.

The inscription reports that it is the mausoleum of Marcus Aebutius Charito, but that one half belongs to Lucius Volusius Successus and Volusia Megiste, who jointly purchased some of it.

Because if you want to go to the Vatican or on the road to Ostia, you'll find the tropaia of those who founded this church.The Greek term used by Gaius—tropaion—usually means a monument or a trophy of victory.

The archaeologist Margherita Guarducci suggested that during the time of construction of the Constantinian basilica, the remains of the Apostle Peter were removed from his original grave and placed in the opening.

[20] The archaeologist pointed to inscriptions in the wall behind the pillar monument including the letters PETR... EN I, as the designation of Peter relics.

Other archaeological sites in Rome also have similar graffiti, suggesting that therein is a commemoration (by Christians) to Peter and Paul as martyrs.

[21] On 26 June 1968, Pope Paul VI announced that following scientific study, the relics of Saint Peter had been identified convincingly.