The Late Empire Part 2 | Roman Architecture | Second edition

The Late Empire Part 2 | Roman Architecture | Second edition

The Late Empire Part 2 | Roman Architecture | Second edition



wall akin to that of Diocletian’s palace at Split. This impression is confirmed by the severe rectilinearity of most of the rooms and their regular, even monotonous disposition, for example, the six rectangular rooms on each side of the frigidarium. Instead of a great domed rotunda, one of the architectural triumphs of the Baths of Caracalla, the caldarium was a rectangular cross-vaulted room with four semicircular apses. However, the greatest splendor must have been the nation which measured c. 48 × 86 meters and covered over three times the area of that in the Baths of Caracalla. At the sides were vaulted halls encrusted in polychrome mosaic, while high screen walls, decorated with a triple order of columns in the manner of the scaenae frons of a Roman theatre, shut the pool off from the surrounding enclosure and adjacent frigidarium. Michelangelo’s transformation of the tepidarium and part of the frigidarium into the church of St. Maria Degli Angeli means that some of the spatial effects of the interior can still be appreciated (Figure 12.8).

The eight granite columns under the triple cross-vault stand in their original positions and the room is still lit by its eight lunette windows. It must be borne in mind however that the vaulting was originally encrusted in polychrome mosaic and that the interior would have had more the jewel-box character of a Ravennate church than the cool Mannerist appearance it has today. In 1749 Vanvitelli was commissioned to enlarge the church and added a choir extending into part of the nation, thus transforming Michelangelo’s nave into a transept. The two architects thus exploited the two major axes of the baths, Michelangelo choosing the long axis and Vanvitelli the short. The 16th-century church and its 18th-century enlargement illustrate the dual axiality inherent in the fully developed imperial bath building.

Figure 12.8  Rome, Baths of Diocletian, cold room (frigidarium), looking NW.

The same rigid planning can be seen in the great palace Diocletian built for his retirement at Spalatum (Split) on the Croatian coast (Figure 12.9). More like a fortified camp than a palace, it reflected the uncertainties of the times and the need to enclose the comfortable Roman world within stout walls. Built between ad 300–306, it lay on the sea coast and was defended by a rectangular wall circuit measuring c. 180 × 216 metres. At each corner was a square bastion with two further square bastions on each of the three landward sides. In the middle of each of these three sides was a gate, flanked by octagonal towers. On the seaward side, there was a landing stage and a single entrance to the palace at water level. Higher up, facing the sea, was a long colonnaded corridor where the emperor could stroll. Two intersecting colonnaded streets divided the complex into four sections. The northern two sections were perhaps barracks, while almost half of the southern sections are taken up by the residential quarters. The route into the latter consists of three successive rooms: a ceremonial courtyard measuring 24 × 13.25 meters, whose sides are formed by 14 arches supported on 12 columns, 5.25 meters high with re-used marble Corinthian capitals. A large octagonal mausoleum opens off the courtyard to the east, and to the west is a small temple whose barrel-vaulted ceiling is adorned with fine stone coffering. The end wall of the courtyard consists of an arcuated lintel within a pediment supported by four taller red granite columns; south of this is a circular domed vestibule; and finally, a suite of palatial rooms with a rectangular hall in the center, flanked by each side by six small rooms. To the west is an lapsed basilical hall, perhaps a throne room, and what looks like a bathing suit. To the east is a large square room with three smaller square rooms opening off it, probably a triclinium (banqueting room). The

Figure 12.9  Spalatum (Split, Croatia), Palace of Diocletian, ad 300–306: plan.

actual rooms do not survive, but their layout can be clearly traced in the substructures below (Figure 12.10). The shapes of the rooms and their arrangement have much of the regularity we have already seen in the Baths of Diocletian in Rome. The palace also has similarities with Romuliana, the palace of Galerius at Gamzigrad in northern Serbia, and the third/fourth-century ad Palatiolum at Melinda. Its outer fortifications echo those of the early fourth-century ad fortified villa at Mogorjelo in Bosnia Herzegovina.

In ad 286, because of its greater proximity to the dangerous Rhine/Danube frontier, Diocletian moved the capital of the western Roman Empire from Rome to Mediolanum (Milan), while he himself resided in Nicomedia. Milan remained the capital until ad 402 when it was besieged by the Visigoths and the court moved to Ravenna. Various Roman remains to survive, notably parts of the Roman wall circuit enlarged by the western emperor, Maximian. The new circuit, built of brick, was about 4.5 kilometers long × 11 meters high and punctuated by eight gates and a number of towers, of which one, with 24 sides, survives to its full height of 16.60 meters. The cardo intersected the decumanus at the forum, west of which was the imperial palace, which seems to have been a very extensive complex covering a large area on the western side of the Roman city. One excavated part consists of a large circular building, 20.70 meters in diameter, which may have been covered by a dome supported on a ring of columns and surrounded by a vaulted annular corridor. Preceding the circular building was a rectangular lobby with apses at each end and north of it a building with three apses and a hypocaust. To the west was a set of three rooms, the central one lapsed with perhaps a similar set of rooms opposite. The SE arm of the decumanus, the road which

Figure 12.10  Spalatum (Split, Croatia), Palace of Diocletian, substructures.

led to Rome, was colonnaded for a distance of one Roman mile outside the walls. Near the NW branch of the decumanus, well outside the city walls, was the Mausoleum of Maximian. Near the palace was a circus, 470 meters long × 85 meters wide, partly incorporated into the defensive wall. One of its towers survives as the bell tower of S. Maurizio. Also nearby was the theatre, a large building raised entirely on substructures and built in the mid to late first-century bc. An amphitheater has been partially excavated to the SW of the city and the large Baths of Hercules to the NE, including parts of a large frigidarium, 50 × 22 meters, with its apse set within the south side of a colonnaded palaestra.

The other Tetrarchs had their own capitals. Trier (Augusta Treverorum) in Germania Superior was the capital of Constantius Chlorus, whose empire included Spain, Gaul, and Britain. Trier was an old-established city on the banks of the Moselle which already possessed a number of imposing monuments, including the amphitheater and the St. Barbara Baths built in the later second-century ad. However, its greatest period of prosperity dates from the time it became Constantius’ capital. His son, Constantine, resided there for a time and completed the palace and basilica begun by his father, as well as building the cathedral, the Imperial Baths, and probably the circus.8 He also built a number of warehouses in the harbor district and the famous Porta Nigra (Figure 12.11). For a hundred years Trier remained the most important city in the west apart from Rome itself. Many of these buildings have survived and taken their place among the most conspicuous architectural remains in the Roman provinces.

The basilica stood on the site of a smaller basilical hall which probably formed part of the residence of the regional procurator (Figure 12.12). It was a large hall with a double square ground plan measuring 100 × 200 Roman feet (29.6 × 59.2 meters) with an apse at one end. There were no internal columns and it had the widest nave of any Roman basilica. The building was lit by two rows of round-headed windows that continued around the

Figure 12.11  Augusta Treverorum (Trier, Germany), Porta Nigra, early fourth century ad.

Figure 12.12  Augusta Treverorum (Trier, Germany), basilica, early fourth century ad: reconstructed view of exterior (left), and plan (right). (After A. Boethius and J. B. Ward Perkins,

Etruscan and Roman Architecture [Harmondsworth: Penguin, 1970].)

apse. The upper windows of the apse were just over a metre lower than the corresponding ones of the nave and were shorter. Also, the two central windows of the apse were narrower than the outer ones. These subtle optical devices give the impression that the apse is higher and wider than it in fact is. These refinements and the unusual construction of the building, which was composed entirely of brick, not brick-faced concrete, are signs of the sophistication of Tetrarchic architecture. Externally the building had a strongly vertical accent because of the blind arcading framing the windows. However, nails and impressions in the brick show that continuous wooden galleries originally ran beneath each row of windows, adding a compensating horizontality. There was a colonnaded courtyard each side of the basilica and the building itself had underfloor heating. Externally it was stuccoed and the window frames were decorated by painted putti and vine scrolls in yellow on a red field. The rich interior was very much in contrast to its rather stark grandeur today. The floor was paved in black and white opus sectile and one of the niches contains traces of mosaic tesserae with blue and green scroll patterns on a gold ground. It also formed part of a larger palace complex of which only a transverse narthex survives. Whether or not the basilica joined up with the complex found a little to the north, under the cathedral, must be resolved by excavation.

The great Imperial Baths were among the largest outside Rome and raise the question of why they should have been built at all when Constantius had only recently finished rebuilding the equally large St. Barbara Baths. The answer may be that they were not for public use, but were connected with the imperial palace, which occupied a large portion of the eastern town. They were designed to occupy two city blocks, half as a gymnasium and half for bathing purposes (Figure 12.13). The main bathing block was much more compactly planned

Figure 12.13  Augusta Treverorum (Trier, Germany), Imperial Baths, early fourth-century ad: restored view (above), plan (below). (After A. Boethius and J. B. Ward Perkins, Etruscan and

Roman Architecture [Harmondsworth: Penguin, 1970].)

than that of the second-century ad St. Barbara Baths, and betrays the hand of a court architect, trained perhaps in north Africa to judge by the ground plan. In the event, it was never finished according to plan because of Constantine’s departure for the east in ad 316, and finally, the entire frigidarium area was scrapped.

The Porta Nigra was probably built by Constantine, but for whatever reason never finished, which explains its somewhat crude surface treatment (Figure 12.11). It owes its preservation to the fact that the hermit, St. Simeon, lived in it and later a church was erected over the gate incorporating most of the Roman structure. The two arched passageways had garrison rooms above and were flanked by two projecting semicircular towers. It followed a well-established Roman type exemplified by the magnificent first-century ad Porta Palatina at Augusta Taurinorum (Turin) which had four arched passageways, two for traffic and two for pedestrians, and was flanked by imposing 16-sided towers. Other Augustan and early imperial gates were of a similar type, such as those at Augusta Praetoria (Aosta), Hispellum (Spello), and Augustodunum (Autun). A feature of these gates is the separate entrance and exit, and the courtyard, where no doubt visitors to the town and their merchandise would be checked. The Trier gate, like the others, was designed to impress. Towers and guard rooms were decorated with rows of half-columns supporting continuous horizontal entablatures, but the effect is clumsy and the work bears signs of haste. Confirmation of this is the fact that inscriptions in the masonry show that the third story went up in three weeks.

Diocletian’s other Caesar, Galerius, who controlled the Danube provinces, made his capital at Sirmium in Diocletian’s province of Pannonia Secunda (northern Serbia). He also built a fortified palace at Gamzigrad in northern Serbia where he was later buried. Perhaps his greatest building achievement was the enormous palace at Thessalonica where he resided, much of which has been uncovered. The city was already well-established by this date and lay on the strategically important via Egnatia which linked Asia and Italy. Galerius built his palace to the east of the old town. The palace proper and an adjoining circus lay to the south of the via Egnatia and his own mausoleum to the north. The via Egnatia was colonnaded at this point and another colonnaded street ran north to the mausoleum (Figure 12.14). The intersection of the colonnaded streets was marked by a four-sided arch. The sides which faced the via Egnatia had three openings, a large one for traffic and two lesser ones for pedestrians. On the other two sides, there was a single opening. As the colonnades abutted against the arch it could not be decorated in the same way as a free-standing structure. This may partly explain the unusual nature of the reliefs, which consist of a series of long, rectangular panels, reminiscent of sarcophagus reliefs, set one on top of the other.

The mausoleum (Figure 12.15) is well-preserved mainly because it was converted into the church of St. George (c. ad 400). It is a domed rotunda with eight barrel-vaulted recesses in the thickness of the drum. Above each recess is a round-headed window, because, although the walls were massively thick, windows rather than an oculus had by then become the established method of lighting a domed room. The structure of the vaults is of interest because pitched brick and mortar rubble is used, a technique that became common in Byzantine times. It also had a double curvature dome, which means that the lower part followed the normal curvature of a hemispherical dome, but, at a point 2.5 meters from the wall, changed to a steeper curvature, adding considerably to the stability of the structure. The crown was a point of weakness in a dome, and it was the shallowness of the crown which caused the dome of Hagia Sophia to collapse barely 21 years after it was completed in ad 537.

At this point, mention should be made of the large Roman villa at Piazza Armerina in Sicily (Figure 12.16). Now dated to the period ad 310–320 it cannot have been built by Maximian as originally thought. It had a loose, rather rambling layout in contrast to the taut planning of Diocletian’s palace at Split. The polychrome mosaics in practically every

Figure 12.14  Thessalonica (Thessaloniki, Greece), Mausoleum of Galerius and monumental approach to it, including the Arch of Galerius across the main colonnaded street of the city, before ad 311: reconstruction. (After A. Boethius and J. B. Ward Perkins, Etruscan and Roman Architecture [Harmondsworth: Penguin, 1970].)

Figure 12.15  Thessalonica (Thessaloniki, Greece), Mausoleum of Galerius and the Arch of Galerius.


Figure 12.16  Piazza Armerina, Roman villa, ad 310–320: plan.

room, covering an area of nearly 0.4 hectares (an acre), link it stylistically with North Africa, but its layout is more reminiscent of Hadrian’s villa at Tivoli. Furthermore, in North Africa both villas and townhouses were of the single-story peristyle type. The main groupings of the entrance courtyard (2 on Figure 2.13), peristyle/audience hall (15 and 30), baths (8–12) and triclinium (46) were loosely related and on differing axes. Like other buildings of the period, the interior dictated the shape of the exterior. The bathing suit, for example, was planned as a series of related interiors, resulting in a jumble of irregular spaces outside. Now that other villas of similar character, but seemingly smaller, have been found at Patti Marina and Caddeddi, both belonging to the fourth-century ad, the Villa at Piazza Armerina is no longer an isolated phenomenon.

When Diocletian went into voluntary retirement he compelled his fellow emperor, Maximian, to do the same (ad 305). Unfortunately, the orderly succession he planned did not materialise. A further round of civil war ensued, this time between Maximian’s son, Maxentius, and Constantine, the son of Constantius Chlorus. Maxentius held power in Italy for six troubled years and built prodigiously during that time. He began work on a large imperial palace for himself on the Appian Way, which included a large circus and a mausoleum. The external length of the circus is 520 meters, less than the 620 meters of the Circus Maximus or the 565 meters of the Circus Varianus of Elagabalus, but it displays many of the refinements to be expected in a building of so late a date. The starting gates (careers) were set out in a tight curve between two tall towers (oppida) built flush with the banks of seats on each side of the track. The dividing strip (spina) was short in relation to the arena as a whole and was angled, as was the seating between the meta Secunda and the careers, a sophisticated device to allow the spectators a closer view of the crucial start of the race. The structure itself was of opus listatum with enormous numbers of amphorae incorporated into the fill of the vaults. His Mausoleum was a domed rotunda with a pedimental columnar porch in front, an arrangement that harks back to the Pantheon. It was set in the middle of a large columnar quadriporticus and was designed to be viewed on all sides. The residential quarter, of great antiquity and only partially excavated, exhibits at least four main building phases. Situated on a low hill, its platform was supported by a late Republican cryptoporticus, 115 metres long, consisting of two parallel vaulted galleries. A very capacious water cistern, 63 × 4.30 meters, was installed in the second-century ad, which fed a bath building and two nymphaea below the terrace. On the terrace various buildings can be seen, in particular a great basilical hall, measuring 33.10 × 19.45 meters, with terracotta heating tubes in the wall, installed when the original villa was turned into an imperial palace by Maxentius.

In ad 307 fire swept the area around Hadrian’s Temple of Venus and Rome, and although it left the outer colonnade undamaged, the twin cells had to be rebuilt by Maxentius. The new cells each terminate in an apse and were roofed with coffered barrel vaults supported on porphyry columns, a material much used in the Late Empire because its color had imperial connotations. Maxentius also began building the adjacent Basilica Nova in ad 308, a colossal building with a broad nave, 25 × 80 × 35 meters high, covered by three cross-vaults buttressed at each side by three barrel vaults (Figure 12.17). The cross-vaults sprang at the level of the top of the barrel vaults and were given visual support by eight Corinthian columns of Proconnesian marble, the only surviving one of which was transported to the piazza in front of St. Maria Maggiore where it still stands. The huge hall was well lit both by windows in the walls of the aisles and by a clerestory of eight lunettes under the cross-vaults. Both the lateral barrel vaults and the cross vaults were decorated with deeply sunken coffers, once elaborately colored and painted. The sheer bulk of the building is still impressive even after the collapse of one set of barrel vaults and all the high vaults. The basilica was an unorthodox building that broke the tradition of its great antecedents like the Basilica Paulli

Figure 12.17  Rome, Basilica of Maxentius (ad 306–312), looking NE.

and Basilica Ulpia, which were divided into nave and aisles by a double order of columns, had clerestory lighting and were covered by wooden roofs. The plan of the Basilica Nova is clearly derived from the frigidarium of one of the large imperial thermae, and as such, it had two major axes. In its original form, its main axis was to be the longitudinal one, and an apse was built at the far end opposite the entrance (Figure 12.18). After the death of Maxentius the basilica was named after Constantine (Aurelius Victor, Caes. 40.26) who finished it, altering its orientation and inserting a new apse in its NE side. He also created a new entrance opposite, preceded by a porch of porphyry columns, in accordance with his policy of promoting buildings on the Via Sacra. A colossal statue of Constantine, parts of which are now in the courtyard of the Capitoline Museum in Rome, was placed in the original apse.

Another monument on the Via Sacra, immediately west of the Basilica Nova and probably of similar date, is a circular domed building, 50 Roman feet (14.8 meters) in diameter, with a concave façade flanked each side by wings, known as the ‘Temple of Romulus’ (Figure 3.2). It had a pair of porphyry columns framing the doorway, whose original bronze doors have been preserved. Pairs of cipollini columns framed each of the lapsed chambers which flanked the central rotunda. The identification of this building has provoked many disputes. It used to be identified, on coin evidence, as a temple erected by Maxentius in honor of his young son, Romulus, who died and was deified in ad 307. A more recent suggestion is that it is the Temple of Jupiter Stator, flanked by shrines of the Penates, whose temple stood at the highest point of the Velia (Livy, 45.16.5). If the original building had to be destroyed owing to the erection of the Basilica Nova, this was the nearest place to rebuild it. More mundanely the temple acted as a vestibule to the Temple of Peace and concealed its alignment, which

Figure 12.18  Rome, Basilica of Maxentius: reconstruction. (After H. Leacroft, The Buildings of

Ancient Rome [Leicester: W. R. Scott, 1969].)

differs from that of the Basilica Nova. The room of the Temple of Peace it gives access to now houses the church of Saints Cosmas and Damian built by Pope Felix IV (ad 527–530).

Constantine was proclaimed emperor by his troops at Eboracum (York) in ad 306 on his father’s death. This brought him into conflict with Maxentius whom he defeated in battles at Turin, Verona and near the Milvian bridge at Rome (ad 312). Constantine later built an arch over the Via Flaminia on the spot where he had marshaled his army for the battle. The Arch of Constantine near the Colosseum was built between ad 312-–315 and also commemorated his victory over Maxentius (Figure 2.11). It was a triple arch similar to the Arch of Septimius Severus, although somewhat wider, measuring 25.9 × 7.4 × 21 meters high. Like the latter, it had three openings, a large central one flanked by two smaller ones, framed each side by four tall, free-standing columns supporting projecting entablatures. Its sculptural ornament was rich and varied, some of it Constantinian, but much of it removed from earlier buildings. Over the lateral passageways were pairs of roundels of Hadrianic date showing hunting scenes set into a porphyry ground and below them narrative reliefs of Constantinian date. The attic was divided each side into three panels by four standing Dacian prisoners perhaps from the Forum of Trajan. The central and largest panel contained the dedicatory inscription, and the lateral ones were filled with pairs of rectangular reliefs of Marcus Aurelius, whose features were replaced by those of Constantine. In the passageways and at the sides of the attic were sections of a magnificent frieze, showing a battle scene. The sculptures in the spandrels and on the column plinths were Constantinian and followed traditional themes.

The Baths of Constantine on the Quirinal (ad 320) are known from drawings by Palladio to have been of the imperial type with the usual succession of the caldarium, tepidarium, frigidarium, and natatio. The frigidarium was covered by three cross-vaults, the central one wider than the other two, with the usual four plunge baths in the corners. Unusually, the frigidarium was prolonged at each end by two further rooms covered with three cross-vaults, each terminating in an apse and each almost as big as the main room. The caldarium has reverted to a circular plan like that of the Baths of Caracalla. Palladio’s plan shows a large curved wall south of the caldarium, with rows of seats.

The so-called ‘Temple of Minerva Medica’ (early fourth-century ad), in the gardens owned by the Licinian family, was a domed pavilion, 25 meters wide with ten sides; one was the entrance and the other nine had projecting semicircular apses (Figures 4.15 and 12.19). The building is a good illustration of some of the building techniques used by late imperial architects. There were large windows in the drum and the envelope of the dome was comparatively thin. Lattice ribbing can be seen in the dome and 18th-century engravings show several of the ribs still standing independently of their filling. This led many to conclude that the ribs were designed to channel stresses in the same way as Gothic ribs. However, the purpose of the ribs was probably to distribute load evenly within the dome. There were also amphorae in the dome above the windows, presumably to channel weight away from them. The ‘Temple of Minerva Medica’ may well have been built by Licinius who had been raised to the rank of Augustus by Galerius in ad 308.

After Galerius’ death in ad 311 and following the defeat and death of Maxentius in ad 312 Constantine met Licinius in Milan and the two promulgated the Edict of Milan, granting toleration to Christianity (ad 313). The edict was a masterstroke in a world that was increasingly seeking spiritual consolation and silenced Constantine’s most vocal critics. In ad 324 Constantine inaugurated a new city to be called Constantinople on the site of Byzantium, an old Greek city on the European side of the Bosphorus, which stood at a critical geographic point between the Balkans and Asia Minor, close to both the Danube and Euphrates frontiers. It also stood at a major intersection of E/W trade. The site itself had many advantages. Roughly triangular in shape, it was surrounded on two sides by the sea,

Figure 12.19  Rome, ‘Temple of Minerva Medica,’ model in Museo della civiltà romana

and had a good harbor in the Golden Horn, whose mouth could be shut off by a chain. Like Rome, it had seven hills and there was plenty of room for expansion. In ad 330 Constantine made it the capital of the Roman Empire. This, more than any other action, spells the end of the old Roman Empire and the change to a new era. The final break the Classical tradition makes this an appropriate point to terminate the story of Roman architecture.


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