The age of Constantine marked a distinct epoch in the history of the Roman Empire. He built a new imperial residence at Byzantium, and renamed the city Constantinople after himself (the laudatory epithet of “New Rome” came later, and was never an official title). It would later become the capital of the empire for over one thousand years; for this reason the later Eastern Empire would come to be known as the Byzantine Empire.

Background: War With Licinius

After defeating Maxentius, Constantine gradually consolidated his military superiority over his rivals in the crumbling tetrarchy. In 313, he met Licinius in Milan to secure their alliance by the marriage of Licinius and Constantine’s half-sister, Constantia. During this meeting, the emperors agreed on the so-called Edict of Milan, officially granting full tolerance to Christianity and all religions in the Empire. In the year 320, Licinius allegedly reneged on the religious freedom promised by the Edict of Milan in 313, and began to oppress Christians anew, generally without bloodshed, but resorting to confiscations and sacking of Christian office-holders.

This dubious arrangement eventually became a challenge to Constantine in the west, climaxing in the great civil war of 324. Licinius, aided by Goth mercenaries, represented the past and the ancient Pagan faiths. Constantine and his Franks marched under the standard of the labarum Chi-Rho, and both sides saw the battle in religious terms. Outnumbered, but fired by their zeal, Constantine’s army emerged victorious in the Battle of Adrianople. Licinius fled across the Bosphorus and appointed Martius Martinianus, the commander of his bodyguard, as Caesar, but Constantine next won the Battle of the Hellespont, and finally the Battle of Chrysopolis on September 18, 324. Licinius and Martinianus surrendered to Constantine at Nicomedia on the promise their lives would be spared: they were sent to live as private citizens in Thessalonica and Cappadocia, respectively, but in 325, Constantine accused Licinius of plotting against him and had them both arrested and hanged. Licinius’s son (the son of Constantine’s half-sister) was also killed. Thus, Constantine became the sole emperor of the Roman Empire.

Foundation of Constantinople

Licinius’ defeat came to represent the defeat of a rival center of Pagan and Greek-speaking political activity in the east, as opposed to the Christian and Latin-speaking Rome, and it was proposed that a new eastern capital should represent the integration of the east into the Roman Empire as a whole, as a center of learning, prosperity, and cultural preservation for the whole of the eastern Roman Empire. Among the various locations proposed for this alternative capital, Constantine appears to have toyed earlier with Serdica (present-day Sofia), as he was reported saying that “Serdica is my Rome.” Sirmium and Thessalonica were also considered. Eventually, however, Constantine decided to work on the Greek city of Byzantium, which offered the advantage of having already been extensively rebuilt on Roman patterns of urbanism, during the preceding century, by Septimius Severus and Caracalla, who had already acknowledged its strategic importance.

The city was thus founded in 324, dedicated on May 11, 330, and renamed Constantinopolis (“Constantine’s City” or Constantinople in English). Special commemorative coins were issued in 330 to honor the event. The new city was protected by the relics of the True Cross, the Rod of Moses, and other holy relics, though a cameo now at the Hermitage Museum also represented Constantine crowned by the tyche of the new city. The figures of old gods were either replaced or assimilated into a framework of Christian symbolism. Constantine built the new Church of the Holy Apostles on the site of a temple to Aphrodite. Generations later there was the story that a divine vision led Constantine to this spot, and an angel no one else could see led him on a circuit of the new walls. The capital would often be compared to the ‘old’ Rome as Nova Roma Constantinopolitana, the “New Rome of Constantinople.” Constantinople was a superb base from which to guard the Danube River, and it was reasonably close to the eastern frontiers. Constantine also began the building of the great fortified walls, which were expanded and rebuilt in subsequent ages.

Constantinopolis Coin. Coin struck by Constantine I to commemorate the founding of Constantinople.

Legacy

Historian J.B. Bury asserts that “the foundation of Constantinople […] inaugurated a permanent division between the Eastern and Western, the Greek and the Latin, halves of the empire—a division to which events had already pointed—and affected decisively the whole subsequent history of Europe.”

The Byzantine Empire considered Constantine its founder, and the Holy Roman Empire reckoned him among the venerable figures of its tradition. In the later Byzantine state, it had become a great honor for an emperor to be hailed as a “new Constantine.” Ten emperors, including the last emperor of the Eastern Roman Empire, carried the name. Monumental Constantinian forms were used at the court of Charlemagne to suggest that he was Constantine’s successor and equal. Constantine acquired a mythic role as a warrior against “heathens.”

Sources