The man who initiated this change was the emperor Constantine, the first Christian emperor and the first emperor to publicly sponsor the Christian Church. His decision to support Christianity was perhaps the single most influential turning point in Roman history, if not the history of the world. It was because of Constantine that Christianity thrived throughout the Roman empire and transformed itself into the world religion it is today. The key to this revolution was the exclusiveness of Christianity, the idea that only one god could be worshipped. The one characteristic that had provoked centuries of persecution would, ironically, become for Constantine its most useful, cherished quality. By tapping into Christian faith, Constantine would allow the Roman empire to flourish one last time, and his regime would be hailed as Rome’s final golden age.
But the man who was responsible for this religious revolution was not himself an exemplary Christian. Flavius Valerius Constantinus was a man of great contradictions, by turns a soldier, a brilliant general and an astute, dissimulating politician. But was he also a man of genuine faith? A sincere convert to the Christian God? Or was he really a self-interested opportunist and evil genius? Central to the problem of understanding his character are the ancient sources: the pagan authors are highly critical of him, while the Christian writers, particularly Eusebius, the bishop of Caesarea, and Lactantius, produced almost lyrical, heavily partisan hagiographies. Despite the conflicting nature of the sources, one clear picture of the emperor’s actions emerges.
To seal his own power and at the same time establish the eminence of the Christian religion required less the Christian virtues of submissiveness, peace and trust than the old Roman virtues of cruelty, vaulting ambition and singular ruthlessness. The people who would fall foul of these characteristics would be not just Constantine’s political enemies, but the closest members of his own family.
FOUR EMPERORS
In the third century AD the Roman world was in crisis. In the space of fifty years (235–85) there were no fewer than twenty emperors, each falling in quick succession to political assassination or death on the battlefield. But it was not just the government that was unstable. The security of the empire too was at an all-time low. In 251 the Goths broke through the forts, watchtowers and ramparts along the border of the Danube from a region north of the Black Sea; they defeated the emperor Decius in battle and eventually sacked Athens. In 259 two Germanic tribes, the Alamanni and Juthungi, also smashed their way across the same border and invaded Italy. The worst year was perhaps 260: the Franks breached the border of the Rhine, marauded their way through Gaul and sacked Tarraco. But there was even worse happening on the eastern frontier. The emperor Valerian was captured by the Persians, enslaved and forced to live out his days bending over so that King Shapur could step on his back to mount his horse. Although Valerian died in captivity, in one sense he lived on: in a macabre inversion of deification, his dead body was stuffed and placed in a Persian temple as a warning to future Roman ambassadors. As shocking as these events were, Romans would find that there was worse in store.
For the best part of fifteen years the Roman provinces of Britain, Gaul and Spain seceded from the empire, and in 272 the Romans permanently abandoned the province of Dacia (modern-day Romania). Perhaps the most extraordinary offensive against Rome came from Palmyra, a rich, semi-independent city on the border of Roman Syria. When its king, Septimius Odenathus, died, his widow, Queen Zenobia, took control. Renowned for her extraordinary beauty, intellect and chastity, she orchestrated and led the conquest of the Roman east: Egypt, Palestine, Syria, Mesopotamia and many of the Roman provinces of Asia Minor all fell under her control before she then proclaimed her son emperor and herself took the title Augusta (empress).
The Romans fought back on all fronts. The most successful emperor was Aurelian (ruled 270–5). In the space of just five, brilliant years he won back the eastern Mediterranean, defeated Zenobia and brought her to Rome as the prize prisoner at his triumph. However, the restoration of the Roman east was just one of the many extraordinary achievements of Aurelian’s short reign. He also drove the invading German tribes out of Italy, forced them back over the northern borders and made peace with them. When that was done, he went on to restore the seceded provinces of Britain, Gaul and Spain to the empire.
But for all their glory, these exploits could not hide what had become so apparent in the third century: the vulnerability of Rome. The ambivalence of the situation is best summed up by Aurelian’s great building legacy. For the first time in the history of the Roman empire the emperor felt it necessary to surround and protect Rome from invaders with a massive wall. It was completed after his death by the emperor Probus (another successful emperor of this period) and still survives in part today. In 285, however, there would come to power a man who would extend that sense of security right across the empire.
Like many emperors of the third century, Gaius Aurelius Valerius Diocletianus (Diocletian) was not from the senatorial and political élite of Rome. He was a low-born soldier from a provincial family who rose to power through the ranks of the military. He had spent most of his time not in the city of Rome, but on the frontiers; in fact, he would travel to the imperial capital only once in his entire life. It was perhaps his experiences on the Danube that spelt out to him the importance of reform if the Roman empire were to survive the preceding decades of crisis. What is certain is that he went about the task of reorganization with extraordinary energy. His reforms focused on money and the army.
The official record of the standing army, the notitia dignitatum, shows how he bolstered the strength of the frontiers by creating new legions. He brought the army under central control and improved soldiers’ pay and supplies. In order to secure the funding of the army, the empire’s economy also needed a radical overhaul. In the course of the third century the coinage of the Roman world had become so debased that the empire reverted to exchanges in kind. Diocletian therefore improved the weight and mint of gold and silver coins, and made them uniform. He also tackled the problem of inflation, and enacted tough social legislation to ensure that tax revenues were successfully and consistently raised. In the process, he established a regular budget for the running of the entire empire.5
Finally, the emperor reorganized the provinces. In order to improve imperial administration, Diocletian broke them down into smaller regions; these in turn were grouped under twelve larger administrative units known as dioceses. The new system allowed closer supervision, as well as the resuscitation of law and finance by local governors and their staffs throughout the empire. However, these impressive, innovative measures were not his most celebrated achievement. The grand idea for which Diocletian would go down in history was his decision on 1 March 293 to create a college of four emperors to rule the Roman world. Diocletian was thus the first emperor to accept that the task of running the Roman empire was too big for one man.
The system, known as the tetrarchy (rule by four emperors), worked as follows. The two senior emperors were both given the title Augustus; Diocletian ruled the eastern half of the empire, while his partner Marcus Aurelius Valerius Maximianus (Maximian) ruled the western half. Each Augustus appointed a junior colleague, and these two deputies were both known by the title Caesar. Gaius Galerius Valerius Maximianus (Galerius) joined Diocletian in the east, while Flavius Valerius Constantius, the father of the future emperor Constantine, aided Maximian in the west. The four men resided in imperial centres pointedly closer to Rome’s frontiers (see map, page 247). In the east Diocletian’s main home was in Nicomedia (modern-day Izmit in Turkey), and Galerius’s in Thessalonica (Greece), while in the west Maximian’s home was Sirmio (Mitrovitz in modern-day Croatia), and Constantius’s was in Trier (Germany). In this way Diocletian ensured that the presence of the emperor of Rome was established in many different areas at the same time.