The marriage ceremony took place in February in the city’s imperial palace, carefully orchestrated and supervised by Constantine himself. The eighteen-year-old bride was the western emperor’s sister Constantia. Like many women of the élite in the early fourth century, she was a Christian – faith was important to her, a key part of her personality. It was a personality, however, less suited to what she was being asked to do by her brother: to marry a man many years her senior, whom she did not know, whom she did not love and to whom she was to be wed for political expediency. Undertaking such a task required a much thicker skin than perhaps Constantia possessed. Yet she was given no choice. Constantine insisted that she marry a man who would be crucial to his plans in the east. The name of her groom was Valerius Licinianus Licinius. He too held the title of emperor.
Born of peasants from Dacia (modern-day Romania), Licinius was nearly in his fifties when he married Constantia. Like many of the other tetrarchs, he had risen to prominence as an able and effective soldier. On campaign on the frontiers of the Danube he had become a close friend of Galerius. It was through him that, just as Diocletian’s system of four emperors was falling apart, Licinius received his greatest break: in 308, at a conference in Carnuntum, he was appointed to be co-emperor of the west with Constantine in place of the dead Severus. When the eastern emperor Galerius died, however, Licinius negotiated a peace with Daia and took partial control of the dead emperor’s territories in the east. But now the fragility of the peace between Daia and Licinius was being exposed. The alliance between Constantine and Licinius, sealed with the dry, diplomatic marriage taking place in Milan, reflected the new lie of the Roman political landscape. The empire was to be shared by the two men alone. There was no room for Daia.
After the marriage ceremony, the alliance was concluded behind closed doors. One can only guess what was said, but the outline is clear. Licinius was to control the east, Constantine the west. Each side would come to the military aid of the other. All was as expected between two emperors redrawing the Roman map. However, Constantine introduced a new, controversial term to their alliance: a policy of toleration of all religions in the Roman world. Although Licinius was not known as a persecutor of Christians, he was certainly pagan in his beliefs. Yet now he was being asked to put his name to a radical new policy in which every Roman was free to worship whichever god he wished. It must have taken him completely by surprise. But if Licinius was reluctant to agree to the policy, Constantine knew how to convince him.
Daia was a renowned persecutor of Christians in the east. The policy of toleration, Constantine might well have suggested, could be the key to winning their support against the eastern emperor. It is easy to imagine that, encouraged by his new Christian advisers, Constantine pressed the importance of this new policy on his pagan brother-in-law. Constantine’s belief in the Christian God was apparently sincere, but it could also be highly useful and expedient. Licinius clearly agreed.
The Edict of Milan, as it came to be known later, was soon proclaimed by both men. It was the first government document in the Western world to recognize freedom of belief. Henceforth persecution of Christians was disowned as morally wrong. But the edict’s principal benefit was more immediate and tangible than that. It decreed that all Church property previously confiscated from the Christians was to be restored to them. Crucially, it not did favour Christians above pagans, but stressed only their equal rights of worship, granting both full legal recognition to ‘follow whatever form of worship they please’. As Licinius did not share his brother-in-law’s religious belief, perhaps he had insisted on that detail. Perhaps he had also made sure that the edict did not commit him personally to the Christian faith; the wording ‘whatsoever divinity dwelt in heaven’ neatly resolved that question.28 Above all, the edict provided a unifying theme for the new empire; it also gave the government of Constantine and Licinius a unified voice of greater strength.
The agreement bonded two very different men. Constantine was well born, younger than Licinius and, so we’re told by Eusebius, charismatic, graceful and good-looking. In winning the west he had proved himself a gifted commander and an astute politician. Licinius, for all his military achievements, was somewhat overshadowed by the western emperor’s brilliance. Indeed, he had good reason to be jealous of the young pretender: Licinius had originally been appointed senior emperor in the west, but it was Constantine who, by defeating Maxentius, had successfully secured it for himself. However, there was no time for indulging in past resentments. There was an aggressor to defeat. Before the conference in Milan was finished, news arrived from the east. Daia had made the first move against the allies: he had crossed the Bosporus, invaded Licinius’s territories in Asia Minor and laid siege to Byzantium. War had been declared.
It took Licinius only a matter of months to gather an army, give chase to Daia’s forces and drive them on to a plain near Hadrianople (modern-day Edirne in Turkey). On 30 April 313, before the battle, Licinius showed he had taken Constantine’s message in Milan to heart: he ordered the rank and file of his army to recite, if not a Christian prayer, then a more perfunctory monotheistic one.29 It seemed to reap immediate dividends. Although Licinius and his 30,000 troops were outnumbered by a 70,000-strong enemy, he and his men enjoyed a comprehensive victory. Daia fled into the Tarsus mountains (in modern-day Turkey) where, to avoid the humiliation of surrender, he committed suicide by taking poison. Buoyed up by his extraordinary victory, Licinius then honoured his agreement with Constantine and, through a letter sent to provincial governors, communicated to the Romans of the east the regime’s new policies.
However, any impression that he was behaving out of a new-found sympathy with the Christian faith was quickly dispelled by his next move. To ensure that no one could stake a rival claim to the eastern empire, Licinius ordered a bloodbath. All Daia’s sympathizers, court advisers and family were executed. In addition, all the living wives and children of the old tetrarchs Diocletian, Severus and Galerius were hunted down throughout the Roman east and murdered. Although some Christian writers of the time heartily approved of the murder of persecutors, perhaps even they would have been shocked by the clinical nature of the purge. With that accomplished, Licinius, the man who had drifted into a toleration of Christianity for political expediency, took sole control of the east and settled down to administering it from his imperial capital of Nicomedia, with his new young bride alongside. The Roman empire enjoyed a new government and a new cohesiveness. But whereas Licinius’s dispassionate toleration of Christianity began and ended with the proclamation and enactment of the Edict of Milan, Constantine’s work, undertaken from his base in Trier, was only just beginning.
Publicly, Constantine continued to steer a shrewd non-committal path: although he declined to participate in pagan sacrifices, he still held the highest office of the pagan religious establishment, held by every emperor since Augustus, that of pontifex maximus (High Priest). The coins issued in his name were slow to depict any Christian symbolism; instead they carried the name of the monotheistic pagan god Unconquerable Sun, and would do so for many years to come. A speech delivered in 313 at Trier survives: it is a masterpiece of ambiguity, emphasizing Constantine’s closeness with the divine, but cleverly not excluding devotion to one faith or another. For all the poise of this balancing act, however, the reality was very different. Constantine had found his unifying theme for the empire. Now he began industriously applying it to the administration and running of the empire.