Old St Peters, the Circus of Caligula and the Phrygianum

The Vatican hill is famous today for the great basilica of St Peters, constructed in the third decade of the fourth century by Constantine, and demolished and rebuilt in the 16th century.  A collection of essays on this building appeared in 2013, edited by R. McKitterick,[1] which contains various interesting snippets.

St Peters basilica in Rome in the early sixth century

St Peter’s basilica in Rome in the early sixth century

Few today are familiar with the layout of the church, so the diagram at the side is useful.  A flight of steps led up to a gatehouse, behind which was a courtyard.  This later contained the immense bronze pine-cone now in the Vatican museum.  Behind this was the church proper, with a nave and two aisles.  The transept gave access to two circular structures, the mausoleum of Honorius (which was turned into the chapel of St Petronilla during the early Dark Ages) and the chapel of St Andrew.

Around the church were all sorts of structures, not depicted on this diagram.  The church was the constant resort of beggars, seeking alms, and doubtless many of the dwellings were hovels.  Theodoric ordered the distribution of grain to them in the late 5th century; Pope Symmachus had shelters constructed for them near the church, and the Dialogues of Gregory the Great record a crippled girl who more or lived in the church until she was healed by a miracle.[2]

A plan of the church by Alfarano, who had been associated with the church since the 1540’s, was published as an etching by Natale Bonifacio in 1590, when construction on the western end of the new basilica was well advanced.  It shows the new construction as a ghost under the old.

Tiberio Alfarano drew the plan in 1571, and the hand-drawn original, known as the Ichnographia, is extant in the archive of the Reverenda Fabbrica di San Pietro.   Comparison shows that the printed version tinkered with the original in various ways, and that not every architectural feature on the drawing appears in the etching.[3]

1590 plan by Alfarano of Old St Peters

1590 plan by Alfarano of Old St Peters

On the south side of the basilica were two circular structures, the chapel of St. Petronilla, actually the Mausoleum of the emperor Honorius; and the chapel of St. Andrew.  Beyond these was the obelisk which now dominates St Peter’s square.

The function of the structure as a mausoleum was remembered as late as the 8th century, but thereafter forgotten until 1458 when a splendid late Roman burial was discovered under the floor, possibly of Galla Placidia and her child.  Another was found in 1519, and finally in 1544 the intact sarcophagus of the empress Maria, wife of Honorius, complete with 180 precious objects in two silver chests, all of which were dispersed or melted down.  The depiction of the basilica in the Nuremberg chronicle of 1493 depicts a round, squat building, which was doubtless the mausoleum.

The structure to the east of it, labelled “Vatican rotunda” in the plan, must predate the basilica as it appears in a gem of the 3rd century.  It was converted by Pope Symmachus in the 5th century into a chapel of St Andrew.[4]

Plan of the mausoleum of Honorius.

Plan of the mausoleum of Honorius.

I have also seen a paper suggesting that the “mausoleum of Honorius” was itself a 3rd century tomb, as was the Rotunda di Sant’Andrea.  The mausoleum was demolished during the building of New St Peter’s, but the Rotunda remained until the 18th century, becoming the church of Santa Maria della Febbre.  A 1629 painting of it, still behind the obelisk (which was surely moved by then?) and with New St Peter’s half-built behind it is available online:

Rotondo di Sant'Andrea, Vatican, Rome.  1629

Rotondo di Sant’Andrea, Vatican, Rome. 1629

And another 18th century drawing by Piranesi[5] shows it nestling next to the basilica, when it was used as a sacristy[6]:

18th century Piranesi drawing.

18th century Piranesi drawing.

The obelisk is an interesting feature, since it is quite unlikely that it was placed there by Constantine.  We learn from Pliny’s Natural History that Caligula erected an obelisk from Heliopolis on the spina of his Circus, in the Horti Agrippinae on the Vatican.[7]  There is apparently consensus, among interested scholars, that the only certain fact about the location and orientation of the circus is that this obelisk was in the centre of it.[8].

Two different circus plans appear online.  I don’t know the source of the second one.[9]

old-st-peters-circus-plan2

old-st-peters-circus-planWhat can be said with certainty is that material from the circus was found during excavations in St Peter’s square, some 5 metres down.[10]

Somewhere nearby, in all this, is the temple of Cybele and Attis, the Vatican Phrygianum.  That such a temple existed in 160 A.D. is recorded by an inscription from Lyons which reads:

Taurobolio Matris d(eum) m(agnae) I(daeae) / quod factum est ex imperio ma tris deum /pro salute imperatoris Caes(aris) T(iti) Aeli Hadriani Antonini Aug(usti) Pii p(atris) p(atriae) / liberorum eius /et status coloniae Lugdun(ensium) / L(ucius) Aemilius Carpus IIIIIIvr Aug(ustalis) item / dendrophorus / uires excepit et a Vaticano trans/tulit ara(m) et bucranium /suo inpendio consacrauit / sacerdote / Q(uinto) Samnio Secondo ab XVuiris /occabo et corona exornato / cui sanctissimus ordo Lugdunens(ium) perpetuitatem sacerdoti(i) decreuit / App(io) Annio Atilio Bradua T(ito) Clod(io) Vibo / Varo co(n)s(ulibus). [11]

Various inscriptions from the end of the 4th century consist of dedications to Cybele by the last holdouts of the pagan aristocracy, suggesting that perhaps the temple was still in use in this period, and recording that the ritual of the taurobolium – being bathed in bulls’ blood – was taking place here.

Pensabene states that the 1959-60 excavations by Castagnoli – I don’t have a reference for these – revealed that there were major works in this area during the Severan period.  The ground level was artificially raised by several metres and a large circular building was constructed whose foundations were contiguous with the obelisk.  The foundations  of this building contained Severan stamps from the first quarter of the 3rd century A.D. The suggestion is that this was to allow the building of a new Phrygianum, and that this was done under Elagabalus, who was enthusiastic for the cult.

The text is accompanied with a very poor quality image which appears to suggest that the Rotonda di Sant’Andrea stands on the site of the Phrygianum, and that the building was originally circular, with a south-facing portico:

old-st-peters-phrygianum

My Italian is not good enough to work out whether Pensabene is suggesting that the Rotondo was, in fact, the carcase of the Phrygianum, stripped of its portico and reused for something else.   But if so, this would certainly be very cramped, next to the basilica, and the presence of the vile eunuch priests and their revolting sacrifices right by the south door sounds rather unlikely to me.  Even if it was a state cult, which Constantine might have been unwilling to interfere with, this seems improbable.

So where was the Phrygianum, if not here?

  1. [1] R. McKitterick, Old Saint Peters, (British School at Rome Studies), 2013.  “Look Inside” on Amazon here.
  2. [2] For these details I am indebted to Paulo Liverani’s paper “St Peter’s and the City of Rome” in the McKitterick volume, of which I was able to read parts via the Amazon “Look Inside”.  The material may be found on p.26; Gregory, Dialogues I, 3.25.1, 108; Life of Symmachus, 53, c. 7, in the Liber Pontificalis I 262; Theodoric in Procopius, Anecdota 26.29.
  3. [3] These details appear in the front matter of the McKitterick book, whose footnotes were sadly inaccessible to me.
  4. [4] Meaghan McEvoy, “Chapter 6: The mausoleum of Honorius” in: R. McKitterick &c., p.119 f.  Accessible via Google Books preview here.
  5. [5] Via Wikimedia Commons
  6. [6] See Italian Wikipedia article here.
  7. [7] Plin. NH XVI.201; XXXVI.74; CIL VI.882 = 31191.  All these references I owe to a remarkable discussion in the Ancient Coins forum here.
  8. [8] Patrizio Pensabene, “Culto di Cibele e Attis tra Palatino e Vaticano”, Bollettino di Archeologia 2010, Online at http://www.archeologia.beniculturali.it/pages/pubblicazioni.html; except that, at the time of writing, this is offline and I was only able to access the article via the Google cache.  UPDATE: Later I found it at Academia.edu here.
  9. [9] The first is from R. Lanciani, Pagan and Christian Rome, 1892,  and appears on Wikimedia Commons here.  Both have been copied from here.
  10. [10] Or so it claims on this website; it would be interesting to have proper details of these excavations.
  11. [11] CIL XIII, 1751. 

6 Responses to “Old St Peters, the Circus of Caligula and the Phrygianum”


  1. Walter Muzzy

    Sorry I can’t reference this but this site very much interests me and I have searched around for info on this Circus over the years.
    I am very positive that the 2nd (tilted) Plan is accurate.
    The 1st is from 1892 and I believe(?) they just guessed at it as they knew where the obelisk was originally located and then just paralleled the Circus Plan with the Basilica?

    I’m very certain that in the past century since that 1st Plan was drawn they have discovered remains of the ‘Starting Gates’ on the right of the Plan roughly where the outlined Circus ends.
    And at the left curved opposite end they discovered a section of the curved Circus wall(I believe it was an accidental discovery at a building construction site?).

    I could be wrong about the “orientation of the circus” although I am certain that is what they had found?
    The obelisk very likely was Caligula’s main showpiece so putting it in the center of the spina I believe makes the most sense plus its height.

  2. Roger Pearse

    That’s very interesting. You know more than I do, I think. It would be most interesting to find some solid data on the excavations, and clearly fairly important to do so.

  3. Stephan

    Is there a connection between the Circus of Caligula and that associated with Nero in the pseudo-Clementine and Acts of Peter? If this holds up doesn’t that mean that Peter’s burial place was connected with the circus narrative?

  4. Walter Muzzy

    Still couldn’t find any “solid data” that I believe I read about the orientation of the circus where the ‘starting gates’ and opposite curved wall have been excavated.
    This website although it doesn’t have the excavation info either also goes with that off-centered Circus Plan and claims it is now the “accepted” Plan?

    http://www.mmdtkw.org/AU0639dCircusBasilicasPlans.jpg
    http://www.mmdtkw.org/ALRITKWBioNote.html http://www.mmdtkw.org/ALRIAncRomUnit6Slides.html

  5. Roger Pearse

    @Walter – thank you for this. Hmm. What we need is to find out who did the excavations.

    @Stephan – Interesting question. I don’t know. I suspect the answer is yes.

  6. Walter Muzzy

    Stephan, I hope I’m understanding your question correctly, if not it is Me.
    The Circus of Caligula and Nero are one in the same although Nero did improve it.
    It was part of the ‘Gardens of Nero’ that Nero opened-up to the people who were homeless after the 64 Fire.
    Tacitus mentions this and also this Circus and the killing of Christians.

    ” If this holds up doesn’t that mean that Peter’s burial place was connected with the circus narrative?”

    Yes and positively believed by ~154AD.
    Look at the Bold outline of the Constantine Basilica above and the aspe location (just for a point of reference).
    When the Church excavated exactly there in the mid-20C (I’m going in reverse of the excavation) they found an empty 1C pauper’s grave in the earth.
    But over the years it had been shored-up twice due to the rising ground level, so someone or somepersons are maintaining it.
    ~154AD (+/- a decade) Christians built a large shrine over this grave even with a trapdoor that like the grave was 11deg off-center (Trophy of Gaius).
    They also walled-in this area which made a fairly large paved courtyard with the tall marble shrine against 1 wall.
    In effect a large room perhaps with a wooden roof where 40-50 people could tightly gather while standing before this shrine.

    All this is supported by the physical archaeological evidence, whether Peter is buried there is debateable.
    I happen to think he is, based on the maintance of the 1st grave to the final elaborate structure only ~90yrs has elapsed.
    A small tight-knit group passing on an important location isn’t that far-fetched.
    I’m 60, my Great-grandfather pointed out the house (next door) that he was born in in ~1895, that’s 119 years ago. Also my grandfather (same street) 101yrs ago.

    Or somewhere in the time-period it became an urban legend that that was Peter’s grave?

    Tacitus; “Covered with the skins of beasts, they were torn by dogs and perished, or were *Nailed to Crosses*, or were doomed to the flames and burnt, to serve as a nightly illumination, when daylight had expired.
    Nero offered his gardens for the spectacle, and was *Exhibiting A Show In The Circus*, while he mingled with the people in the dress of a charioteer or stood aloft on a car.

    Hence, even for criminals (Christians) who deserved extreme and exemplary punishment, there arose a feeling of compassion; for it was not, as it seemed, for the public good, but to glut one man’s cruelty, that they were being destroyed.”



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