We are very grateful to Prof. Pablo Aparicio Resco for his kind permission to reproduce these images of a very interesting project he has been working on, a virtual reconstruction of the ancient basilica of St Peter. (Video and images from PAR – Arqueología y Patrimonio Virtual and 3D Stoa – Patrimonio y Tecnología.)
As I am sure our readers already know, the original building was constructed by the Emperor Constantine in the earliest days of the Peace of the Church; the traditional date of its consecration is November 18, 326. By the mid-15th century, it was over 11 centuries old, and in very poor condition, as was much of Rome after the neglect entailed by the long papal residence in Avignon (1309-76), and the events of the Great Schism (1378-1417). In the 1440s, the Florentine scholar León Battista Alberti (1404-72) was serving as architectural advisor to Pope Nicholas V (1447-55), and pointed out to him that a stretch of the north wall (on the right as one looks at the façade) totaling about half its length was sagging well over three feet off the perpendicular. After various rather half-hearted attempts to restore it, the building was deemed unsalvageable, and in the beginning of the 16th century, the project of replacing it was begun by Pope Julius II (1503-13). Julius’ project, however, stalled repeatedly, and would not really begin in earnest until many years later, when it was assigned to Michelangelo by Pope Paul III in 1545.The Constantinian basilica was placed so that the apse would enshrine the grave of St Peter, which, however, was in the middle of a very large necropolis on the Vatican Hill. This required not only that a good many burials be disturbed, but also that a massive part of the hill itself be moved, amounting to about a million cubic feet of dirt. As a very good guide once pointed out on a tour of the modern excavations under the new basilica, this alone makes for a very strong argument in favor of the authenticity of the gravesite as that of St Peter. Next to the site was a ready-made flat space formerly occupied by the so-called Circus of Nero (more properly, of Caligula), where the church could have been built more easily. Constantine would be unlikely to expend so much time and energy flattening the hill, unless he needed to do so to include the grave.
This view, therefore, shows us how one would originally have approached the church, walking through the part of the Vatican necropolis that remained undisturbed, (the modern Via della Conciliazione.)
Here, we see the basilica from the south side. The obelisk was originally mounted on the wall that ran down the middle of the circus, which the Romans called “spina - the spine ”, and around which the chariots turned during races. By Constantine’s time, the circus was gone, but the obelisk, an 84 foot-tall block of solid granite weighing about 330 tons, remained in its place until 1588, when it was transported roughly a quarter of a mile away, to stand in front of the new basilica.
The façade seen from inside the great courtyard in front of the basilica.
Two cross section views: the first shows the transept and apse, with the site of the grave...
while the second shows the whole church through the length of the nave. This also gives a very good idea of the massive platform which Constantine built and on which the whole of the original complex, courtyard and basilica, rests. Towards the lower left, we see a large imperial mausoleum built next to the left transept in the middle of the 5th century. This structure was round on the outside, but octagonal on the inside; a narthex was later built to connect it to the basilica. In subsequent centuries, six of its eight internal niches were made into chapels, with that opposite the door being dedicated to St Petronilla; for a long time, this chapel was under the patronage of the kings of France. In 1498, Cardinal Jean Bilhères de Lagraulas, the French ambassador to the Papal court, commissioned his own funerary monument to be added to the chapel, from a 23-year-old Florentine sculptor named Michelangelo Buonarroti. This is, of course, one of the most loved and admired sculptures in the entire world, the Pietà.
A more complete render of the complex as it would have been seen ca. 450 AD.
A detached view of the original monument over the grave of St Peter, which would have been visible and visitable (presumably under supervision) through the door at the front of the large marble box in the middle. In its original conception, the basilica’s primary role was to welcome groups of pilgrims who wished to visit the tomb of the Apostle Peter. The altar was therefore behind the box, and invisble from the nave. Pope St Gregory the Great would have the entire area around it elevated, and a new altar built on top of the box; the barest remains of it can still be seen when one visits the excavations today.
The remaining images give us a sense of the internal decorations, on analogy with what we know about the original church, and other Constantinian churches.
