Arch of Constantine
A cavalry battle that started at a defile on the Cassian Road at saxa rubra and continued downhill to the Tiber and across the Milvian Bridge – whence its conventional name – is the best place to start an account of “Byzantine Rome,” by which we mean a Rome that was still part of the Roman Empire but no longer its capital, which shifted to Constantinople. I may continue the series further to explore a Rome still locked in a Byzantine cultural orbit but, for now, the above definition should suffice.
Parts of Constantine’s Rome still survive. Today, it’s possible to walk Pons Fabricius, one of the two bridges (along with Pons Cestius) that once crossed Tiber Island. And a few hundred metres south, the remains of the Aemilian Bridge (renamed Ponte Rotto, the Broken Bridge) rise above the river. Parts of the quay for unloading marbles, the marmorata, can also be seen; a memory of when goods were unloaded at Ostia or Porto and reshipped in smaller boats upstream to the river wharves at the foot of the Aventine.
Pons Fabricius
Other survivors include some of Rome’s eleven (nineteen if you count splits) aqueducts, the twelve-mile wall (enclosing seven square miles) built by the emperors Aurelian and Probus (raised by Maxentius to almost twice their original height), the new Senate House (after the old one burned down in AD 283): the Curia Senatus and, finally, Santa Maria degli Angeli e dei Martiri, which rises within the remains of the Baths of Diocletian (vaster even than the Baths of Caracalla) on the Esquiline.
Constantine completed many of Maxentius’ structures. The Basilica Nova, a colossal hall (even now an impressive ruin), for instance, was known as the Basilica Constantini in his own time. Elsewhere, the current Cosma e Daimiano was thoroughly remodelled by both emperors, probably for use as an audience hall for their city prefects. To the east, on the site of the Licinian Gardens, still stands today the ruin of a ten-sided domed garden hall called the Minerva Medica. To the southeast, in the vast complex of a third-century palace (known as the Sessorium) rose an apsed hall built by Maxentius and Constantine (its tall ruin stands next to S. Croce in Gerusalemme). And to the west of the present church of the Lateran, a huge mansion was remodelled under Constantine and decorated with murals that displayed the mythical ancestors of his dynasty.
Basilica Nova
The Illyrian also had his own projects. These included an equestrian statue on the Forum, which has now disappeared but was familiar to Romans as late as the eighth century. His Baths, which covered the southern slope of the Quirinal (nowadays the Rospigliosi Palace). On the Forum Boarium (the old cattle market near the Tiber) at least one monument dates from his reign: the Janus Quadrifrons, a huge four-sided arch covered with marble plaques with 96 niches for statues. His most famous monument, however, will always remain his triumphal arch near the Colosseum and across the Ostian Way. Dedicated by the Senate in AD 315, it proclaims Constantine as having won the empire by the guidance of the Godhead, instinctu divinitatis (an intentionally vague phrase). Far less ambiguous was the statue he set up at the Basilica Nova, which carried the labarum marked by the Chi-Rho.
The above is just a flavour of Constantine’s Rome. Suffice it to say, fourth-century regionaria surveyed the city and found 28 libraries, 6 obelisks, 8 bridges, 11 fora, 10 basilicas, 11 public baths, 18 aqueducts, 9 circuses and theatres, 2 triumphal columns, 15 monumental fountains, 22 equestrian statues, 80 golden statues, 74 ivory statues, 36 triumphal arches, 290 granaries and warehouses, 856 private baths, 254 bakeries and 46 brothels.
Basilica di Santa Maria degli Angeli e dei Martiri
The general character of the city would have remained unchanged from the early empire. Villas and tenements rubbed shoulder to shoulder, Trastevere – then as now the most densely populated quarter – was where immigrants from the East crowded, and only the rich occupied the outer greenbelt that extended beyond the Aurelian walls and rose to the crests of the hills. On these estates (and in between) stood the tombs of the wealthy: the mausolea of Caecilia Metella, of Maxentius’ son Romulus, of the Gordians at Tor de’ Schiavi are surviving examples.
Yet there were signs of change afoot. Church houses (or house churches), for instance, multiplied. Identified by the name of the original holder of title to the building, examples include titulus Clementis, Anastasiae, Caeciliae, Chrysogoni etc. rented, purchased by or donated to the Church. Twenty-five are known to have existed in Constantine’s reign. Occasionally, in the years of religious tolerance prior to AD 312, Christians may have built plain halls – witness (Rome’s first church?) S. Crisogono, its walls now lie buried alongside the medieval church in Trastevere at Ponte Garibaldi.
Santa Costanza Mausoleum Mosaic of Traditio Legis
Cult centres at the graves of martyrs also flourished. Underneath S. Sebastiano on the Via Appia, one served for the veneration of Peter & Paul whose feast or relics (or both) were probably moved to the spot in AD 258. Oddly perhaps in hindsight, the locus of St Peter’s cult – marked by a small aedicule called the “Trophy” i.e. sign of victory over death) – on the Vatican Hill was quite commonplace thanks to its location within a cemetery of lavish mausolea.
This all changed in the winter of AD 312 when Constantine decided to build a cathedral at the Lateran for the Roman bishop. The domus Fasutae served as early as the Autumn of AD 313 for the meetings of a church council held under the auspices of the emperor. Adjoining it, the barracks of the imperial horseguards were razed (for picking the wrong side in his conflict with Maxentius) and in its place the new church was built (its remains survive in the foundations and walls of S. Giovanni in Laterano). Shortly afterwards the Empress Dowager, Helena, built a palace church among the buildings of the Sessorian Palace. Endowed with a relic of the True Cross (hence its name: S. Croce in Gerusalemme) its old walls are still visible from the outside.
Curia Iulia
In sum, the Lateran, its baptistery and S. Croce in Gerusalemme were the only structures built inside the walls of Rome by Constantine and his family for the Church. The real (i.e. organic, bottom-up) building programmes took place near the cemeteries despite the fact Mass was celebrated only on a martyr’s anniversary and no permanent clergy was attached to them.
One such covered cemetery or funerary hall survives (though remodelled) at the aforementioned S. Sebastiano, constructed over the cult centre of the Apostles on the Appian Way (the present church fills only the nave of the old one). Another of an almost identical plan (though even larger at 98 metres long) stood at the Tiburtine Road at the foot of the cliff where the grave of St Lawrence was venerated. A third basilica has been traced on the grounds of the imperial villa ad duos lauros on the Via Labicana adjoining the tomb of the martyrs Marcellinus & Peter. Attached to its front portico rose a huge mausoleum, still preserved, which sheltered the sarcophagus of Helena. A fourth example was built by Constantine’s daughter, Constantia, on her estate near the grave of the (impeccably Roman) martyr Agnes on the Via Nomentana. Large parts of the outer walls survive to their full height. Against its flank she placed her own mausoleum, S. Constanza.
Aurelian Walls
Finally, it can be easy to forget that St Peter’s, too, was founded by Constantine primarily as a covered cemetery and funerary hall that oversaw burials, commemorative banquets and the veneration of a martyr. Hence the mausolea that crowded its walls. One, S. Maria della Febbre, was even older than the church (and survived until the eighteenth century).
Arch of Janus