Constantinople possessed the most extraordinary natural advantages of any city in the ancient world. It was founded on a peninsula at the entrance to the Bosporus, which linked the Sea of Marmara with the Black Sea, and was protected on two sides by water and on the third by a narrow isthmus, which could easily be fortified. The sheltered inlet of the Golden Horn was a huge, and defensible, natural harbor. This was the point where all the land routes from Europe and Asia converged, uniting the eastern and western parts of the empire.
The strategic importance of the site was revealed by the events of the civil war between Constantine and Licinius, when the latter's fleet was defeated at the battle of Chrysopolis (Scutari). The victor chose to re-found the previously modest Roman city of Byzantium. Building began at the end of 324 and the foundation dedication was celebrated in the emperor's presence on May 11, 330. It is not clear what role Constantine intended for his new city. Having now achieved his aspiration to be sole ruler of the empire he could hardly envisage replacing Rome as its capital, and he had made a point of returning there to celebrate his own vicennalia in 326. Constantinople, rather, was modeled on the other imperial cities that had emerged during the tetrarchic period, comparable to but outshining Trier, Antioch, and nearby Nicomedia.16
Constantine left intact the old acropolis of Byzantium, containing the main pagan temples, although both Eusebius and the epigrammatist Palladas indicate that it was Constantine's intention to desacralize the city's old pagan monuments and buildings.17 The imperial palace, where the ruler would conduct business in seclusion, and the hippodrome, where his people could gather for racing and other spectacles, and to acclaim the emperor on his public appearances, also both lay within the earlier city limits. The imperial household moved into its new quarters and the future emperor Julian was born in the palace two years after Constantinople had been founded. The imperial residence probably originally took a form similar to Diocletian's palace at Split, or the imperial complex built by Galerius at Gamzigrad, Felix Romuliana, in modern Serbia (see p. 396), but the building was enlarged by his successors until it extended south to the sea walls facing the Propontis. The hippodrome, with seating for 80,000 spectators, was an enlargement of a pre-existing stadium. The loggia for the imperial family and high officials was directly accessible from the palace and looked across the race track to the seating occupied by the circus partisans.18 Adjoining the hippodrome on the north were two public buildings also incorporated from the former Roman city, the Baths of Zeuxippos, and a square with colonnades on four sides leading to a meeting hall for the city's Senate (later to be known as the Augustaeum).
Constantine now extended the city westwards. The Mesê, a broad colonnaded street, ran up the middle of the peninsula. Along this was placed the omphalos, an oval piazza, and at its center a porphyry column which carried a statue of the emperor. It is important to recognize that Constantine did not overwhelm his city with ecclesiastical foundations. The church historians say that he built a church for St Eirene (Socrates, HE 1.16), an extra-mural basilica for the local martyr St Mocius (Sozomen 8.17.5), and a church for St Acacius (Socrates, HE 6.23). The first church of St Sophia was completed by Constantius II. Eusebius naturally asserted that he created a city that was purged of pagan idol worship (VC 3.47), but Zosimus emphasized that he preserved a temple of the Dioscuri by the hippodrome and created sanctuaries for Rhea and for the Tyche of the Romans (Zosimus 2.30–31). Much the most important of Constantine's religious foundations was the shrine of the Holy Apostles (located on the site of the Ottoman Fatih mosque), which was designed and built towards the end of his life as his mausoleum. Here he was entombed at the center of a circular or cruciform building, elaborately decorated with golden ceiling coffers, in the midst of twelve cenotaphs, which symbolized the tombs of the apostles themselves (Eusebius, VC 4.58–60).
Constantine constructed new fortifications enclosing the peninsula about three kilometers west of the old walls of Byzantium and enlarged the area for building by extending the land mass into the sea both on the side of the Golden Horn and on the Sea of Marmara. A street grid was established to accommodate new settlers, and senators who had supported the emperor began to construct their own houses. Main streets ran north to docks on the Golden Horn and south to the Propontic shore. Two large harbors were built here, the first by Julian, the second by Theodosius. The Mesê continued to another intersection marked by a monument popularly known as the Philadelphion, a statue group which was supposed to depict the sons of Constantine embracing one another. The statue in question appears to be none other than the famous porphyry group depicting the four tetrarchs, probably originally from Nicomedia, which was taken to Venice by the crusaders after the sack of Constantinople in 1204 (Plate 3.1).19 The public places of the city were adorned with statues and other monuments collected from cities in the eastern empire.
This was the template for the development of the New Rome. Provisions were made immediately to supply the city with tax grain from Egypt. According to the Notitia of about 425, the city had four large warehouses for storing provisions close to the Prosphorion harbor at Sirkeci on the Golden Horn, and two others close to the harbors on the Propontic side (Notitia Urbis Constantinopolitanae; Zosimus 3.11). In all the sources attest as many as twenty-one public granaries in the city. It has been estimated that four kilometers of quayside would have been needed to provide docking for the grain ships during the sailing season.20
Securing the city's water supply was a major issue. Themistius, in a panegyric for Valens written in 376, evokes the image of a city dying of thirst before the emperor constructed an aqueduct over 1,000 stades (over 180 kilometers) in length, bringing the water to the city from the nymphs of Thrace (Or. 13, 167d). This enormous project multiplied by a factor of ten the amount of water available from springs close to the city. The water was stored in huge rectangular cisterns built on the hills, from which it could be distributed as required to the rest of the city. Large new cisterns were built in 421, in 459, during the reign of Anastasius, under Justinian in the 530s, and under Phocas in 609, attesting the increase in the city's population and the growth of its needs. Smaller underground cisterns were built for private houses.21 The famous arches attributed to Valens, which are a conspicuous feature of Istanbul today, may however be part of the earlier Hadrianic system built for Byzantium. Constantius had begun to construct imperial baths, the Thermae Constantianae, in 345, but these were not finished until 427, and evidently lacked a water supply at least until Valens’ day.
The public areas of the city were greatly expanded in the late fourth and early fifth centuries. Theodosius began work in 393 on a new civic center, the Forum Tauri, at Beyazit, where he erected a column which was a faithful copy of the Roman column of Trajan, Theodosius's great Spanish predecessor. A mounted statue of Theodosius set up in the same square deliberately evoked comparison with the bronze equestrian figure of Trajan at Rome. Theodosius thus realized in Constantinople the ambition that Constantius had conceived in 357 on his visit to Rome (see p. 335). In contrast to Rome, marble was readily available at Constantinople, brought from the quarries of Proconnesus in the Propontis, where architectural elements (column shafts, capitals, and gable pieces in particular) were prefabricated before being shipped to the building sites of the capital. The most imposing pieces to be identified are gigantic column drums intended for the Forum Tauri.22
The most representative monument of Theodosian Constantinople was the obelisk and its sculpted and inscribed base, probably set up in 391/2, which still stands in the spina of the hippodrome. The inscriptions displayed Greek and Latin verses which celebrated both the achievement of raising the obelisk to its new position (the task had been supervised by the prefect of the city Proclus) and Theodosius’ defeat of the usurper Magnus Maximus (ILS 821). The reliefs are a visual realization of the power structure of the late Roman state and are a key to understanding the political relationship between the emperor and his subjects (Plates 3.4, 5.2, and 5.3).
The most important development of the early fifth century was the completion of new fortifications in 413, the walls built by Theodosius II's praetorian prefect Anthemius and rebuilt after an earthquake in 447.23 Attackers were confronted by a twenty-meter-wide moat, an outer wall five meters high, reinforced with circular and square towers, and behind them the main rampart, twelve meters high, also reinforced by massive towers (Plates 9.2 and 9.3). The towers served as barracks for the standing army in the city (CTh. 7.8.13). Constantius had started to build the sea walls, but these were reinforced and completed in the 440s, to meet the naval threat of the Vandals. The fortifications of Constantinople were not breached until the city fell to the crusaders in 1204.24 The Theodosian walls increased the fortified area of the city by about 40 percent. It appears that this area was not largely devoted to new housing, but contained large villas, monasteries, churches, and several large cisterns. The wall of Constantine remained intact, dividing the city into an urban and a suburban region, both secured from attack. Further important protection was provided by the fifty-kilometer-long ditch and land wall which was built across the Thracian peninsula from the south coast east of Selymbria (Silvri) to the Black Sea, and reinforced by a series of small garrison forts (see p. 129).
Plate 9.2 The Golden Gate at Constantinople, constructed as a triumphal arch for Theodosius I, c.390, and later incorporated into the fortifications of Theodosius II (S. Mitchell)
Plate 9.3 The Theodosian Walls of Constantinople (© Hercules Milas/Alamy)
As at Rome, the sharp growth in the number of churches in the city occurred not in the fourth but in the fifth and sixth centuries. During the ostentatiously pious regime of Theodosius II and Pulcheria, the Notitia Urbis lists fourteen churches, including the two earliest that survive today, the Church of the Theotokos at Chalkoprateia, the copper market west of St Sophia, built by Pulcheria, and the Church of St John Studios, near the new Theodosian walls. The biggest increase occurred in the time of Justinian. Procopius’ Buildings describes thirty-four new foundations by the emperor himself, a list headed by the great surviving structures of St Eirene and St Sophia. The rapid expansion of church building is not only to be explained by the liturgical needs of the growing population, but by the ambitions of wealthy families, including the emperor's, to display their power by ostentatious ecclesiastical foundations. The clearest example of this rivalry is provided by the Church of St Polyeuctus, built between the second and third hills of the city by Anicia Juliana, the matriarch of one of the wealthiest senatorial clans of Constantinople. The dimensions and design of her church deliberately matched the Old Testament blueprint for the Temple of Solomon at Jerusalem and the surviving dedicatory poem for the building asserted her claim to be matched as a builder with the emperors Constantine and Theodosius (Anth. Pal. 1.10).25 Justinian rose precisely to this challenge in building his own greatest church, St Sophia, above the ruins that had been burnt to the ground in the Nika riot of 532. St Sophia, completed between 532 and 537, was the greatest building of the Justinianic period, the realization in stone and mortar of the emperor's personal sense of religious destiny (Plate 4.2). The achievement of Justinian and his architects is measured in Procopius’ description of the building's spiritual impact:
Whenever anyone enters this church to pray, he understands at once that it is not by any human power or skill, but by the influence of God, that this work has been so finely turned. And so his mind is lifted up toward God and exalted, feeling that He cannot be far away, but must especially love to dwell in this place which He has chosen. (Procopius, Buildings I, 1.61)
The initial design for the huge dome was too precarious, and the structure collapsed in an earthquake of 557 (Agathias V, 3–9), but the will to complete the project remained indomitable, even after the death of its two architects, Anthemius of Tralles and Isidore of Miletus. Reconstruction was completed in 562. Two contemporary accounts of the building survive, a lengthy description in Procopius’ buildings (Procopius, Buildings I, 67–78), and a poem by Paul Silentiarius, written after the re-dedication of the great church in 562.26
Constantinople, like Rome, had an impact on the empire that extended far beyond its walls. It acted as a powerful magnet to settlers. Rich senators accompanied Constantine at the foundation, and there was continuous immigration by members of the ruling class, notably the Spanish clique that arrived in the wake of Theodosius I.27 The poor inhabitants came in vast numbers for different reasons, attracted by the prospects of employment and a guaranteed food supply. Constantine made initial provision for the state annona to feed 80,000 inhabitants with grain brought from Alexandria. By the time of Justinian, the number of recipients may have reached 600,000.28 As at Rome, the ultimate responsibility for distributing provisions lay with the city prefect. Although the practice had its origins in the distribution of free grain to citizens at Rome in the late republic, the creation of universal Roman citizenship had transformed the legal basis for the organization, and the state annona of the late empire was transformed into a service designed to support the proletariat of large cities. Annona systems existed not only at Rome and Constantinople, but also at Alexandria, Antioch, and even in the provincial Egyptian town of Oxyrhynchus.29 The tentacles of the supply chain to Constantinople stretched into the Black Sea, to Egypt, the main source of grain, and to southern Asia Minor, which was one of the chief sources of olive oil. Procopius (Buildings 5.1.7–16) tells us that the island of Tenedos, at the entrance to the Dardanelles, became a major entrepôt, where large ships discharged their cargoes into smaller ones which could make their way more easily through the straits and into the Sea of Marmara. The time saved enabled them to make two or even three trips from Alexandria in a single season. The demands of the capital had a transforming effect on the economic structures of the regions that supplied the annona. Production concentrated in the hands of large-scale, well-organized producers. The primary trade in foodstuffs generated essential secondary industries, in particular the production of amphoras and shipbuilding. Merchant shipping was one of the major industries of the east Mediterranean. The continuing prosperity of Egypt in late antiquity and the growth of large estates there were due to the fact that the harvests of the Nile Valley found a permanent market outlet in Constantinople (see pp. 376–9).30