Possible imperial mausoleum at the base of the bell-tower of the Basilica di San Pietro in Perugia, from the Giornale dell’Umbria

Yesterday’s Giornale dell’Umbria had a cover story about an ongoing study that aims to determine whether the Roman emperor Gaius Vibius Trebonianus Gallus, a Perugine native who ruled from AD 251-3, was buried in a mausoleum that today serves as the foundation for the marvelous bell-tower of the Basilica di San Pietro, next to medieval gardens that I visited a few weeks ago.

The story raises interesting questions about the role the city played for the Vibian clan when one of its sons became, briefly, the most powerful man in the world.

The Metropolitan Museum of Art in New York has a rare monumental bronze imperial statue, and it happens to be of Trebonianus Gallus. The statue is 7 ft. 11 inches tall — rather bigger, of course, than real-life Gallus.

Trebonianus Gallus, born in AD 206 in Perugia, came from a prominent Perugian family, and he climbed the cursus honorum, becoming senator, consul, and provincial governor. In the latter capacity, he commanded troops defending the province of Upper Moesia, along the southern bank of the Danube river (today occupied by Serbia, Bulgaria and Romania, etc.). Moesia had been won for Rome by the emperor Trajan from AD 101-106 (when we were in Rome, we spent some time gazing up at the column that illustrates those campaigns). The Goths were putting immense pressure on that frontier by the middle of the third century AD, and the reigning emperor Decius and his son were suddenly killed in the campaign against them. To avoid a leadership vacuum (since the imperial system did not have a good strategy for succession), Decius’ troops proclaimed Trebonianus Gallus emperor; he had demonstrated a good record of military and political leadership to that point.

Since Rome was still the center of power, Gallus had to get back there to get his post confirmed, so he grant some contraversial conditions to the Goths in securing a peace. By the time he got back to Rome, the city was in the grip of a deadly plague. He made an effort to make sure all victims were properly buried (even the poor), but he did not respond to a major Persian advance into Rome’s eastern provinces (and accordingly lost Syria). When his gubernatorial successor on the Danube frontier, Aemilianus, marched on Rome to seize power for himself, Gallus prepared poorly, and his own troops mutinied and killed him. See R. Scott Moore’s biography of Gallus for details.

Below is a translation of the news story (here’s the original Italian). Note that it is a work in progress by the named scholars. Ellipses mark a few details I’ve left out because they are only of interest to residents of Perugia. I’ve also added links and illustrations, as well as [clarifying words in brackets].

Basilica San Pietro is at #15 (upper right); the Arco Etrusco is #20 (far left); Porta Marzia is #12 (at center-right). Click to enlarge the map.

PERUGIA – Few know who Gaius Vibius Trebonianus Gallus really was. An emperor who, from A.D. 251-252 A.D. held the fortunes of an immense Roman Empire that was falling apart and who died with his son Volusianus at the hands of traitors, after having fought on the borders of the empire against the barbarians. Well, the Perugian emperor … is still being talked about. Yes, because thanks to historical interest shown for years and the continuous examination of the subject by regional councillor Stefano Vinti, and to the studies of the Superintendency for Umbrian Archaeological Heritage, it is possible to hypothesize the presence of archaeological remains dating back to the age of Trebonianus Gallus near the belfry of San Pietro, next to the School of Agriculture of the University of Perugia.

Arco Etrusco (currently under restoration); from Wikimedia.

Some time ago already, in fact, Vinti began to ask questions and to submit them to the relevant authorities about the presence of the mausoleum found at San Pietro. One starts with what remains of Trebonianus in Perugia: “There are two inscriptions, says Vinti, “both bearing the words Colonia Vibia, in memory of the granting of colonial rights (ius coloniae) ​​by the Emperor to his hometown, and which also remind us of his clan, the gens Vibia, from which he derived the nomen of Vibius. One inscription is located above the famous Arco Etrusco, which now faces the piazza Grimana; the other is inscribed above the Arch of Porta Marzia, also Etruscan, set by the architect Antonio da Sangallo the Younger into the east bastion of the sixteenth-century Rocca Paolina to decorate an entryway along the present via Marzia.”

Arco di Porta Marzia (the ‘Gate of Mars’); from Wikimedia

Since then, interest in discovering the truth about where the Perugian emperor was buried has increased apace, thanks to the brilliant intuition of Dr. Mario Pagano, Superintendent of Umbrian Archaeological Heritage, who arrived at the hypothesis that a mausoleum next to one of the most important complexes in the history of late antique and medieval Perugia could be attributed to Trebonianus Gallus, or at least that the structure contains the pieces (‘spolia‘) [of the mausoleum]. At this time studies are still in progress and Dr. Pagano, who is doing an article on the area in order to find an answer to his hypothesis, reports that “the church was erected in a prominent position on the Tiber plain on a mount called Caprarius, also later called… Calvarius, not far from the church and venerated tomb of St. Costanzo, which supports the idea that the main Christian cemetery of the city occupied this area.” If one tries to provide a date for the construction, there is still some uncertainty, but, “comparison with other churches built in the cemetery area suggests, as writes Pagano, “that also in this case, as in other similar cases, it belongs to the first half of the fifth century AD.”

Cloister and Bell-tower of the Basilica of San Pietro, Perugia (photo by R.o.b.e.r.t.o.)

The approximate date of construction and an analysis of the circular mausoleum found at the base of the bell-tower could prove the existence of a burial chamber, in which the forgotten Emperor of Perugia could be buried. “It should be thought of, writes Pagano, “as a huge circular mausoleum of almost 18 meters in diameter, with a square base of three rows of square blocks of travertine that we can imagine was surmounted by a circular aedicula with statues of the principal persons buried there, which now makes up the medieval and Renaissance bell-tower base of the church.” Continuing the analysis, “the mausoleum, while not blocking the entrance door of the early Christian basilica, appears to affect strongly the architecture of the basilica, occupying the axis of a side aisle and part of the central nave and constituting an optical reference both for those who arrived from the city, and for those who came from Rome.”

The grandeur of the mausoleum appears to confirm the thesis that it was the property of a “person and a family so important to the history of the city, that they had to be tolerated and even absorbed into a Christian architectural design.” In addition, the shape and configuration of the mausoleum suggest a construction date close to the “restitutio augustea” in Perugia [that is, mid-third century AD].

‘Colonia Vibia’ over the Porta Marzia in Perugia: briefly, a Perugian emperor

But is this really the mausoleum dedicated to Gaius Vibius Trebonianus Gallus? According to Pagano, “everything leads us to believe that the mausoleum of the gens Vibia, the most prominent family in the city, ought to be where the emperors had to be buried: C. Vibius Trebonianus Gallus and his son Volusianus (who died in AD 253 near Terni or Forum Flamini), natives of Perugia, who gave the city of Perugia the status of a colony, as documented by the grand inscriptions on the city gates. The senatorial clan to which they belonged, the Vibii, was evidently still very relevant in the fifth century AD.”

It is only a hypothesis at the moment, but studies and the forthcoming article could dispel any doubt about the ownership of the mausoleum. A funerary monument that, as Pagano notes, “seems typical of the Etruscan senatorial aristocracy of the Roman age and could be, in my opinion — due to its peculiarity and the fact that [its design] also appears on Etruscan urns — linked to Etruscan ritual divination practices. Ground-Penetrating Radar prospection and archaeological trenches, currently being planned, will be able to confirm and better illustrate some of the hypotheses and reconstructions proposed here.” While waiting for the (frozen) funding needed to complete the research, one can only hope that the work done so far by the Superintendent and his team can bring to light elements that have made us think about the presence of a forgotten Emperor right next to the basilica of San Pietro, “the most eloquent expression of the well-being of Perugia in late antiquity, in the first decades of the fifth century.”

The hypothesis is interesting; the evidence is circumstantial; we await ground-truthing.