PETRIANO, MUSEO. — This was a special building where, for a time, the principal sacred and profane monuments were suitably arranged. These had been saved after the demolition of the ancient Constantinian Basilica or had come to light during the excavations carried out to lay the foundations of the new Basilica of St Peter, and were later placed in the Vatican Grottoes. The initiative was taken by Msgr. G. De Bisogno, treasurer of the Revered Fabric of St Peter. Approved by Benedict XV, the construction work was completed at the beginning of the pontificate of Pius XI, so that by 1925 the new Museum was ready to welcome its first visitors.
In the 14 rooms into which it was divided, there were not only the aforementioned monuments but also various relics relating to both the old and the new Basilica, such as drawings, plans and models, including the notable wooden model devised by Antonio da Sangallo the Younger and commissioned in 1539 from his pupil Antonio Labacco at the order of Paul III; the wooden model of Michelangelo’s dome, ordered by Paul IV (1556–59); and the clay model showing what the ancient Basilica looked like, with the annexed buildings, before the 16th century. Models of the so-called “flying bridges,” devised by Niccolò Zabaglia (1674–1755), a brilliant illiterate stonemason of St Peter’s, and used for restoration work on the upper parts of the building, also aroused curiosity.
Among the various artistic monuments displayed in the Museo Petriano, special admiration was reserved for the tomb of Sixtus IV, a fine bronze work by Antonio Pollaiuolo, completed in 1493 and signed by the master; transferred from the old to the new Basilica, it had finally been placed in the Chapel of the Sacrament. Other famous artists represented in the Museum included Mino da Fiesole, whose remains of the tomb of Paul II were admired; Melozzo da Forlì, with a fragment of a fresco depicting the head of St Peter; Giotto, with an angel, a remnant of the famous mosaic of the Navicella, still extant above the central entrance of the portico; and Carmuccini, with the Incredulity of St Thomas, etc. Finally, among the oldest monuments, noteworthy was the sarcophagus of the consul Sextus Petronius Probus (AD 371) and his wife Anicia Faltonia Proba, which until 1649 had served as the base of the baptismal font; it came from the mausoleum of the Anicii, demolished in 1450 by Nicholas V when work began on the new Basilica.
During the war period, the Museo Petriano was used as an office for the search for prisoners of war, but it no longer exists today, having been stripped of almost all its precious material, most of which has been returned to the Vatican Grottoes.