by David Potter
Diocletian came out of retirement in AD 308, but made it clear that he was only doing so to aid Galerius. Given the great support he still commanded and the potential for enormous bloodshed, it is fortunate for all involved that Diocletian had a real abhorrence of civil war. After a confusing spring in which Constantine and Galerius squared up to one another, while Maximian tried to remove Maxentius from power, failed and fled to Gaul, a meeting was summoned at Carnuntum in Lower Austria, from which Maxentius was excluded. The outcome of the conference was that Galerius agreed that Constantine could call himself Augustus in the regions he controlled already, and Caesar elsewhere. This made it possible for Galerius to appoint a new Augustus, an experienced general named Licinius (c. AD 250–325), to replace the fallen Severus. With the principle of collegiate government re-established, and with Galerius clearly recognized as the senior member of the college, Diocletian retired once more to his palace, where he lived in peace for the final three years of his life, tending his vegetable garden.
It is one of the ironies of this period that Galerius, who tried so hard to uphold Diocletian’s system, even constructing a massive retirement palace of his own at Roumaliana (Gamzigrad) in the Balkans, was fated to succumb to a malignant disease, possibly bowel cancer, a few months before his former mentor. His principal achievement had been to keep the peace between his fractious colleagues. During this uneasy peace, Constantine took advantage of the lull to hone his skills as a general, while Maximinus did nothing more constructive than work up a profound loathing for Licinius, who had effectively been promoted over his head. Maximian lived with Constantine until AD 310, when he suddenly tried to seize power for himself in southern France while Constantine was away campaigning on the Rhine. The attempt failed, and Maximian committed suicide (it is unclear whether he did so with or without the active collusion of his son-in-law).
Immediately after the death of Galerius, the surviving Augusti and Caesars split into two factions: Maximinus allied himself with Maxentius, and Constantine with Licinius. The war that loomed in AD 312 looked ominous indeed; the two sides had roughly equivalent armies, and neither had a clear strategic advantage. The threat of Maximinus constrained Licinius from lending significant aid to Constantine, while Constantine could not help Licinius until he had dealt with Maxentius.
Showdown with Maxentius
The invasion of Italy was a daunting task. Maxentius’ army was supplemented by a series of fortified cities in the north, while Rome itself had so far proved unassailable. Constantine was plainly worried, and now set out upon a spiritual odyssey that would transform the history of Europe. While in Gaul, he had followed what was by now the traditional practice of letting it be known that he had a guardian divinity – in his case Sol Invictus. This may have been more than just self-aggrandizement on Constantine’s part, since he was evidently a deeply pious person. But what if his faith in the gods was misplaced? It would not have escaped his attention that Galerius had been a devoted follower of the traditional gods yet had still failed utterly. In the spring of AD 312, Constantine suddenly announced that he placed all his confidence in mens divina, the ‘Divine Mind’. It is not clear what he meant to signify by this term, and contemporary polytheistic propagandists writing immediately before and after the invasion supply no clue. It is altogether likely that, with an army that consisted of traditional believers behind him, Constantine did not wish to be more specific. He may well have speculated that the one deity that Galerius despised, the Christian God, now held the key to his fate. Later commentators are in no doubt that this was the point when Constantine became convinced he had been given signs that the God of the Christians would be on his side.
The uncertainty over the precise nature of his conversion is fully in accordance with Constantine’s generally enigmatic character: he could be rash yet patient; he had the ability to listen and to change course when he realized he had made an error, yet placed enormous confidence in his own judgement; although no intellectual, he was extremely bright. He could be both compassionate and utterly ruthless. But what was beyond all dispute was Constantine’s genius as a military commander, possibly the greatest general Rome had seen since the time of Julius Caesar.
Constantine’s invasion of Italy was one of the most brilliant military operations in ancient history. Sweeping aside Maxentius’ northern armies, and drawing them into battle before they could take refuge behind their fortifications, by the early autumn he was already advancing on Rome. The effect of the defeats in the north was that Maxentius could not retire behind the walls of Rome and wait for Constantine to exhaust his supplies. His reputation in tatters, he had to risk all in one final encounter. So it was that Maxentius led his army out of Rome on 28 October to a place near the Milvian Bridge called Saxa Rubra, north of the Tiber, to challenge Constantine. The final battle was swift and decisive. Maxentius was killed in the rout, and Constantine entered Rome in triumph.
The alliance with Licinius
Within weeks of the victory over Maxentius, Constantine was on his way back north. Meeting Licinius at Milan, he spoke to him of the power of his new god, and cemented their alliance by giving him his half-sister, Constantia, in marriage. It was now up to Licinius to deal with Maxentius’ ally Maximinus.
Maximinus proved an obliging enemy; his crossing of the Dardanelles at the head of his field army in April, AD 313, saved Licinius the trouble of waging war in hostile territory. So thorough was the victory that Licinius won near the city of Adrianople, some 150 miles (220 kilometres) west of modern Istanbul, that Maximinus could mount no serious resistance when Licinius pursued him back into his own territory. As Licinius closed in on his stronghold at Tarsus in Anatolia (southern Turkey), Maximinus realized that the game was up and committed suicide. During his retreat, one of Maximinus’ last acts had been to issue an edict declaring that the Christians in his part of the empire, against whom he had staged a series of persecutions, were free to practise their religion in peace. Licinius, whose wife was a Christian, followed this with an edict of his own restoring property confiscated in the persecutions. The combination of these edicts with the earlier edicts of Constantine restored Christianity to the position of equality with other religions that it had enjoyed in the years after Gallienus.
Although Licinius and Constantine both believed that Christians should have the freedom to worship, there was little else upon which they agreed. While it was possible for decrees of one emperor to be recognized as legally binding in the territory of the other, in practice the tendency was increasingly for the two to go their separate ways. Key documents have survived showing that Licinius’ army was granted slightly different benefits from that of Constantine, and the bureaucracies of the eastern and western empires had little interchange with one another. Although there were now effectively two Roman empires, each one consisting of six of the 12 dioceses, neither man yet dared to take a step that would signal a decisive break. Nor would either yet conceive a succession plan. Licinius’ position was straightforward, since he, as yet, had no son. For Constantine, the situation was somewhat more complex. He had a son, Crispus, the offspring of his marriage, while he was in Diocletian’s court, to a woman named Minervina, who had died before his marriage to Fausta. Initially, Constantine was equivocal in promoting the claims of this boy, whose circumstances were reminiscent of his own. However, the situation changed radically between AD 315 and 316, when first Constantia and then Fausta produced sons. Between the birth of the two boys, Constantine and Licinius concluded an agreement that their sons should not be placed in the line of succession, and arrived at a compromise whereby Bassianus, the husband of Constantine’s half-sister Anastasia, would be declared Caesar. Yet shortly after the birth of Fausta’s first son – which meant that, if he stuck to the compromise, Constantine would now be sacrificing two of his children’s hopes for one of Licinius’ – Constantine executed Bassianus on a charge of treason. Anticipating conflict, both emperors had already prepared for war.
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bsp; Constantine attacked in the autumn of AD 316 and succeeded in driving Licinius out of most of his territory in the Balkans, but then overreached himself. Manoeuvring with great skill, Licinius cut his adversary’s supply lines, forcing Constantine to make peace on far less advantageous terms than might otherwise have been the case. The result was that Constantine gained just one of the three Balkan dioceses on a permanent basis and was obliged to recognize three Caesars: Constantine’s eldest son, Crispus, the infant Constantine and the infant Licinius. The treaty was concluded on 1 March, AD 317, and remained in force for seven years.
Although Constantine spent much of his time after signing the treaty with Licinius commanding his army in the Balkans, he still found time to sire three more children with Fausta, two daughters and a son. By AD 324, with a household full of potential heirs, Constantine decided to be rid of Licinius for good. Declaring war in the summer, he drove his enemy out of the Balkans by the early autumn and forced him to surrender at Nicomedia in November. The defeated Licinius was granted clemency and sent into exile in Thessalonica. But shortly thereafter, Constantine ‘discovered’ that he was at the centre of a conspiracy and ordered his death.
Constantinople
No sooner had he defeated Licinius than a new problem arose for Constantine regarding the Christians of the eastern empire. Adherents of the faith were engaged in a bitter dispute over the true nature of God, arising from ideas developed by Arius (c. AD 250–336), a theologian from Alexandria. The Arian controversy, as it became known, had caused a deep rift in Christian communities, which were split between rival leaders. Constantine had some experience of such disputes, having already tried to resolve an extremely unpleasant schism that developed in the Christian community of North Africa soon after he defeated Maxentius. On that occasion, the schism had resulted not from doctrinal differences but from practical disagreements over whether it was better to appease persecutors of the faith or to resist and run the risk of greater violence. When Constantine’s officials arrived in North Africa to restore property seized in the persecution, they found themselves confronted by two diametrically opposed factions that had adopted entrenched positions. To determine which had the better claim, Constantine referred the matter to a series of church councils, all of which ruled against the party which claimed that resistance to the authorities was in accord with God’s will. The defeated faction refused to abide by the decisions of the councils, and after a brief bout of persecution, Constantine washed his hands of the whole affair. Yet although his intervention in this dispute was unsuccessful, Constantine had learned a valuable lesson: third-party arbitration would not stop Christians from fighting with each other. He would need to intervene personally to get the warring parties around the negotiating table.
Thus it was that in AD 325, Constantine summoned the bishops of the east to a grand council at Nicaea, a town on the coast of Anatolia. After a show of listening to both sides in the dispute, the emperor offered a compromise formula that delivered a new creed expounding the nature of God. This was a seminal event in the history of the Christian Church. Since not only eastern but also a few western bishops were present, the council of Nicaea was the first conference that claimed jurisdiction over the Christian community as a whole. It was also an important moment in relations between the secular and religious leaderships. Constantine’s action showed that the emperor could exert authority in spiritual matters, thus setting a precedent for later emperors who would regard such intervention as part of their remit.
Even before Licinius surrendered, Constantine conceived the idea of building a new capital in the east. Perhaps because of its association with earlier regimes, Nicomedia was deemed unsuitable, and so his choice finally came to rest on the ancient city of Byzantium on the Bosphorus. This settlement, which was ideally placed to give the emperor easy access to Rome’s northern frontier on the Danube and its eastern frontier on the Euphrates, was now to be refounded as Constantinople. The design of the new capital was intended to mirror Constantine’s attitudes towards both government and religion.
The new city arose with remarkable speed. The centrepiece of the building programme was the imperial palace, with a massive Hippodrome attached, seating 80,000 people, as a venue where the emperor could meet his subjects. In addition, he ordered construction of a vast new church, while retaining the city’s older temples. Christianity was to be presented as a faith that could supplement and enhance the regime without requiring that the old ways be repudiated. The same principle was applied to the way in which the new city was populated. Constantine did not force people to come to the city, but instead rewarded those who chose to move. Likewise, rather than create a new senate, an act that would have offended senators in Rome, he simply accorded privileges to senior officials who chose to relocate to his capital. To beautify the new capital, cities throughout the east were invited to send famous monuments of antiquity to adorn its public spaces.
Turmoil and divisions
Although Constantinople was never meant to replace Rome, but rather to augment it, its founding did nevertheless raise the question of how the western empire would now be run. Constantine was personally committed to the east, but his son Crispus, who had distinguished himself during the war with Licinius, had long been based at Trier. However, before the end of AD 326, the peace of the imperial household was shattered, with Crispus arrested, tried for treason and executed, and Fausta banished into internal exile, where she died within a couple of years. The reason for this dramatic turn of events is shrouded in mystery. A later pagan writer concocted a lurid tale of how Fausta had lusted after her stepson, and when he refused her advances, claimed that he had attempted to rape her, which led to his execution. According to this same author, Fausta’s plot had been exposed by the emperor’s mother, causing an enraged Constantine to lock his wife in an overheated bath house until she died. Nothing in this story is borne out by the facts as we know them. A more likely explanation was that a major rift had occurred between father and son regarding the future direction of government, and that Fausta had objected to the treatment of her stepson. Constantine seems to have interpreted Crispus’ disagreement as potentially treasonous and acted precipitately. Perhaps a sign that he came to regret what happened was the fact that Fausta’s sons remained in line for the succession, and that he never remarried.
Now lacking an empress, Constantine was forced to turn to his mother for help. The aged Helena was sent on a grand tour of the east, where she visited Palestine and was present as a massive new programme of church building was inaugurated in the Holy Land. The sacred sites of the Christian religion were honoured with their own churches, such as the Church of the Holy Sepulchre in Jerusalem, built over the supposed tomb of Christ, as well as churches at the site of the Ascension and the Nativity. Her participation in these events later gave rise to the legend that she found the fragments of the True Cross – on which Christ was crucified at Golgotha – in Jerusalem.
While Constantine’s guiding principle was that religion should act as a unifying force in the empire, the exercise of secular authority during his reign caused ever-deepening divisions. As the central government asserted more control over local affairs – an inevitable consequence of Diocletian’s policy of smaller, more numerous provinces – each region found that it had increasingly less freedom to define its own relationship to the centre. Conversely, the more extensive governing structures generated regional bureaucracies that were perfectly capable of functioning on their own. Constantine’s empire was still split into multiple prefectures (though usually five, with one praetorian prefect assigned to the area north of the Alps, another to Italy, a third to Africa, a fourth to the Balkans and the fifth in the eastern provinces), while his army was now firmly divided between frontier units, the limitanei, and units attached to mobile reserve formations, the comitatenses, a system begun by Diocletian. In addition to this functional compartmentalization, the army was also divided into three main commands – the West, the Bal
kans and the East – with each front under its own magister peditum (master of infantry) and magister equitum (master of cavalry). The different parts of the army, like the different bureaucracies, were increasingly regional in character, with the western sector being heavily recruited from Franks and Alamanni as well as people from within the frontier zone, while the Balkan army increasingly included large numbers of Goths, who had replaced the earlier tribes north of the Danube over the course of the third century. It was only in the east, where the central Anatolian plateau offered a seemingly endless supply of hardy recruits to serve alongside Syrian and Armenian troops, that the imperial army could still broadly be described as ‘Roman’ (though many of these soldiers were only acclimatized to Roman ways after they had enlisted).
In the late 330s, as Constantinople expanded into a major city, Constantine confronted the need for a firm plan of succession. He still had three sons and two daughters by Fausta, and a number of nephews, the children of his half-brothers and sisters. Although much of his adult life had been spent eliminating rivals, Constantine felt that there was no intrinsic reason why the empire should have only one emperor. Indeed, the fact that a man who had ruled the entire empire on his own for 13 years should feel that collegial government would work best when he passed on speaks volumes about how deeply divided along regional lines the empire now was. Considering his succession, Constantine even looked beyond his immediate family, elevating his nephew Dalmatius (d. AD 337) to a position equal to that of his own sons as Caesar and making another nephew, Hannibalianus (d. AD 337), king of Armenia, with the evident intent that he should rule a fifth prefecture as soon as it could be acquired. This prefecture would be in Iraq, and in AD 337 Constantine began to plan a massive invasion to bring this region finally under Roman control.