The Development of Roman Military Strategy: The Empire’s Army in Different Phases

The last phase of Roman history is the history of the empire: it began around 27 B.C. and ended in 476 A.D. This imperial phase came after both the monarchical phase and the republic phase. This final five centuries of Roman civilization can be further subdivided into three segments, according to historian Edward Luttwak. These three spans reflect three different goals for the imperial military. They are, in chronological order, expansion, maintenance, and defense.

Like most historical generalizations, these three phases of the empire cannot be taken as precise demarcations. There is some blurring of the distinctions and some overlapping of the time segments. Edward Luttwak presents the three phases as he devises them:

With brutal simplicity, it might be said that with the first system the Romans of the republic conquered much to serve the interests of a few, those living in the city — and in fact still fewer, those best placed to control policy.

Even within this first phase, there was development, both of the basic principles of this phase, and of what would become features of the next two phases. “During the first century,” Luttwak writes, “Roman ideas evolved toward a much broader and altogether more benevolent conception of empire.”

Although the first phase was characterized by expansion, it was in 9 A.D., during this first phase, that a German chieftain, known as Arminius or Herrmann, successfully attacked, defeated, and largely destroyed “three legions and auxiliary troops” commanded by Varus. Thus features of the latter two phases — maintenance and defense — are seen already in the first.

The clever act of bestowing fully Roman citizenship on many people living in the colonies or provinces marks the second phase. Enjoying their citizenship, and the rights and privileges it brought, these people developed an attachment to the empire, and were willing to support it and serve in its defense.

Under the aegis of the second system, men born in lands far from Rome could call themselves Romans and have their claim fully allowed; and the frontiers were efficiently developed to defend the growing prosperity of all, and not merely of the privileged. The result was the empire of the second century, which served the security interests of millions rather than of thousands.

During the third phase, in which Edward Luttwak sees the Roman military as largely defensive during the gradual contraction of the empire, echoes of the first phase are seen in, e.g., attempted Roman expansion eastward into Persia and Persian-controlled territories.

Under the third system, organized in the wake of the great crisis of the third century, the provision of security became an increasingly heavy charge on society — and a charge very unevenly distributed, which could enrich the wealthy while certainly ruining the poor. The machinery of empire now became increasingly self-serving, with its tax collectors, administrators, and soldiers of much greater use to one another than to the society at large. Even then the empire retained the loyalties of many, for the alternative was chaos. When this ceased to be so, when organized barbarian states capable of providing a measure of law and order began to emerge in lands that had once been Roman, then the last system of imperial security lost its last source of support, men’s fear of the unknown.

In addition to dividing the military history of the empire into these three phases, Luttwak also conceptualizes the fall of the empire as having one of its many roots in the growing awareness on the part of the Roman populace of the fact that the Germanic tribes could be, and often were, reasonable. The end of the empire would not be a descent into total chaos and destruction, but could be a someone orderly transition of power.

Indeed, when the Germanic chieftain Odoacer ended the empire in 476 A.D., he was careful to observe a number of customs and phrases as he presented himself, and a number of Roman institutions were left functioning in place, like the Senate.

Julian the Apostate: His Ambivalence

The history of Christianity during the Roman Empire is bumpy and complicated. The Roman Empire began around 27 B.C. and Christianity began around 30 A.D.

During the earliest years of Christianity, the Roman officials regarded Christianity as simply a variety of Judaism: Jesus being a rabbi, the events starting the Christian faith having taken place in Jewish territory, and the first groups of Christians being Jews.

After the first few decades, the Romans came to see Christianity as something distinct from Judaism, but this understanding didn’t make a practical difference: both religions were persecuted by the Roman authorities. Thousands of Christians and Jews were arrested, jailed, beaten, and killed.

Despite this oppression, the Christian faith spread rapidly. The new religion gained members from all social classes and in every region within the empire. Conditions, however, gradually began to improve for Christians.

On April 30, 311, the Emperor Galerius issued The Edict of Toleration. Between February and June 313, Emperor Constantine and Emperor Licinius, ruling jointly at the time, issued the Edict of Milan. These two documents established Christianity as a legally accepted option alongside the various forms of paganism in the empire.

Christianity was tolerated, but not accepted. A century later, in 410, Christians were being harassed as pagans blamed them for military defeats, primarily when Germanic tribesmen sacked the city of Rome in that year. Christianity was an all-purpose scapegoat: it could be blamed for any social difficulties in the empire.

After Constantine’s edict in 313 A.D., Christianity did not become the state religion of the empire, as is sometimes reported. Christian baptism was not a legal requirement. Quite the opposite: Christians were a minority of the empire’s population, and Christianity remained on the margins of society.

The imperial career of Julian makes this clear; historian Edward Arthur Thompson reports that

Julian (Flavius Claudius Julianus) (331 - 363), commonly called Julian the Apostate, Roman emperor A.D. 361 - 363, was born at Constantinople, the son of Julius Constantius, a half brother of Constantine the Great.

Julian’s family tree alone gave him a headstart on the road to power and fame. In addition, he was smart, obtained a good education, and proved himself practical in matters of military leadership.

He had a half brother named Gallus. Like Julian, Gallus was destined for leadership roles in the upper levels of the imperial administration. Edward Arthur Thompson explains that Emperor Constantius II promoted Gallus:

In 351 Gallus was elevated to the rank of Caesar and appointed to rule at Antioch; and it seems to have been about this time, when he was associating with the best-known philosophers of the day, that Julian secretly abandoned Christianity.

The career of Gallus came quickly to an end in 354, when the emperor Constantius II suspected him of disloyalty and had him executed.

Julian was aware that Constantius II was paranoid — even if the paranoia was perhaps justified by the ambitions of power-seeking men — and so remained alert for any threats from the emperor. Meanwhile, Julian’s military successes gave him political momentum, and his reputation was so good that the men of his army named him augustus — effectively emperor — by acclamation. He was certainly now a target for the wrath of Constantius II.

Julian’s spiritual involvement was at this point in time ambiguous. Although a pagan, he had occasionally attended Christian worship events, perhaps out of curiosity, or perhaps for the thrill of engaging in an event which was not in the social mainstream. But that would soon change, and his attachment to paganism would become a determining factor in his actions:

On Jan. 6, 361, he attended a church service, perhaps for the last time.

Frequently on the move, as his army’s task was to keep the Germanic tribes away from the city of Rome, Julian spent some time stationed at a city called Naissus, modern-day Nis, in Serbia. It was while Julian was at Nis that he learned that Constantius II had died, probably of natural causes.

Some reports claim that Emperor Constantius II asked to be baptized shortly before his death. Whether Julian received those reports, and how they may have factored into his thinking, is not clear.

In any case, with the emperor’s death, the immediate threat to Julian’s life was removed — of course, there would be others, as was the case for nearly every Roman emperor. Julian would now effectively be emperor and sole ruler of the empire. Perhaps it was this elevation that moved him from an interest in, and attraction to, paganism, toward a commitment to paganism. From the beginning of the empire until Julian’s reign, the vast majority of Roman emperors were pagans.

Julian appears to have become openly a pagan while still at Naissus.

Having become emperor in 361, Julian now wanted to build his reputation as emperor. While Jews and Christians had abandoned the practice of animal sacrifice for three centuries, it was still a central activity among the pagans. Julian hoped to solidify his emperorship’s reputation by these pagan rituals. While Christianity was a minority religion in most of the empire, Antioch was one city in which a large percentage of the residents were Christians. Julian received an unenthusiastic reception there:

Envious of Alexander the Great, Julian wished for military glory in the east and entered Antioch on July 19, 362. Associating closely with the pagan orator Libanius, he frequented the temples, multiplied his sacrifices to the gods, but failed to win much popularity with the predominantly Christian citizens.

Although now a dedicated pagan, Julian still pursued the tactic of religious tolerance, at least until late 362. He saw the growing numbers of Christians as a threat and a mystery. They were a threat to the credibility of paganism, and they were a mystery because their membership grew despite the movement’s lack of political, military, or economic might.

Julian hoped to pattern a new version of paganism after Christianity:

On Aug. 1, 362, Julian was still recommending religious tolerance. He decided to reorganize the pagan priesthood, appointing a chief priest in each province, and his letters of instruction to these men were most detailed: he wished to equip the pagans with an organization comparable to that of the Christians.

When Christians expressed disagreement with his paganism, and with some of his harsher actions, Julian abandoned the policies of tolerance, as Edward Arthur Thompson explains:

Christians were forbidden to teach in the schools, certain bishops (including Athanasius) were exiled, taxes were levied on Christian clergy, preference was given to pagans in appointments to high office, etc.

Although Julian was now openly persecuting Christians, he still wanted to see paganism restructured along Christian lines. He wanted the pagans to have the same success that the Christians were having, as Timothy Dalrymple writes:

In the fourth century, a Roman emperor who was so riddled with religious skepticism and pagan ideology that he was known as Julian the Apostate could not help but recognize the transformative power of Christian love and care. In a letter to a pagan priest, Julian wrote, “The Christians support not only their poor but ours as well; all men see that our people lack aid from us.” Julian’s letter went so far as to urge the pagan priest to mimic the charity of the Christians.

Among the Romans, the Christians were sometimes referred to as “Galilaeans.” The full quote from Julian’s letter reads:

For it is disgraceful that, when no Jew ever has to beg, and the impious Galilaeans support not only their own poor but ours as well, all men see that our people lack aid from us.

Julian was not the only Roman to notice the counterintuitive growth of the Christian movement. Other texts from the era express similar bemusement and similar observations, e.g., Pliny the Younger in his letters to Trajan.

It puzzled many Romans that such a movement with no financial or legal power could attract so many followers so quickly. Among the Christians, some Roman social patterns were violated. Pliny writes of a Christian gathering led by female slaves; sitting in the audience were free male Roman citizens who listened attentively and regarded these speakers as authoritative. This represented a reversal of the Roman social order: slave vs. free, male vs. female, citizen vs. non-citizen. Yet the movement grew, attracting ever more members from all demographic categories.

The Christians were persistent in providing food and medical care to anyone who needed it. Christian missionaries carried this ethic of service to every corner of the empire. Brian Palmer writes about such activity:

The missionaries don’t profit personally from their work. They are compensated very poorly, if at all.

Julian hoped to instill such determination among the pagans. His death in 363, while fighting in Persia, brought an end to his efforts. It’s worth noting that for the remaining 113 years of the Roman Empire, which ended in 476, all the emperors were Christian.

While many Romans deprecated, admired, or were mystified by the rapid growth of the politically powerless Christian movement, Julian had a slightly different response: he hoped to co-opt Christianity’s method and duplicate Christianity’s success for paganism.

Julian’s plan didn’t work.