The Fall of the Roman Empire: A New History

by Peter Heather

  As Roman power moved east of the Rhine, different Germanic groups were quite as likely to fight each other as to fight the Romans, and the results could be as brutal as the Teutoburger Wald. There is little discernible cultural difference between these groups, and it was essentially different political identities that divided them, and through which struggles for control of the best lands and other economic assets were fought out. Late in the first century, for instance, a coalition of their neighbours turned on the Bructeri, and invited Roman observers to enjoy the spectacle, reportedly, of 60,000 people being massacred. Tacitus’ Annals also record a fight to the death between the Hermenduri and the Chatti, and the eventual destruction of the landless, and hence troublesome, Ampsivarii: ‘In their protracted wanderings, the exiles were treated as guests, then as beggars, then as enemies. Finally, their fighting-men were exterminated, their young and old distributed as booty.’7

  It could hardly be clearer that nineteenth-century visions of an ancient German nation were way off-target. Temporary alliances and unusually powerful kings might for a time knit together a couple or more of its many small tribes, but the inhabitants of first-century Germania had no capacity to formulate and put into practice sustained and unifying political agendas.

  Why did Roman expansion fail to swallow this highly fragmented world whole, as it had done Celtic Europe? The halting of the legions’ progress through northern Europe has often been attributed to Arminius’ great victory, but like the destruction of the legion commanded by Sabinus and Cotta in 54 BC, the massacre of Varus’ command was a one-off event for which the Romans duly extracted revenge. Germanicus’ visit to the Teutoburger Wald in AD 15 was part of another major campaign against Arminius’ Cherusci. In the course of it, a second Roman force was ambushed by Arminius’ warriors, but this time the outcome was different. Although hard pressed for a time, the Romans eventually lured their opponents into a trap, with a predictable outcome: ‘The Germani went down, as defenceless in defeat as success had made them impetuous. Arminius got away unhurt [but] the massacre of the rank and file went on as long as fury and daylight lasted.’8 The Romans were assisted by Segestes, a second leader of the Cherusci, who, like many Gallic Celtic chiefs in the time of Julius Caesar, saw considerable advantages in his territory becoming part of the Roman Empire. Not even the Cherusci, let alone the Germani as a whole, were united in their resistance to Rome, and the Teutoburger Wald did not stop the advance of the legions in its tracks. More Roman victories followed in AD 16, and about three years later Arminius was murdered by a faction of his own tribesmen. His son was brought up in Ravenna. Arminus had won one huge, fluke victory, but the underlying reasons for the halting of the legions on the fringes of first-century Germania were altogether different.

  LOGISTICS MADE IT likely enough that Rome’s European frontiers would end up on river lines somewhere. Rivers made supplying the many troops stationed on the frontier a much more practical proposition. An early imperial Roman legion of about 5,000 men required about 7,500 kilos of grain and 450 kilos of fodder per day, or 225 and 13.5 tonnes, respectively, per month.9 Most Roman troops at this date were placed on or close to the frontier, and conditions in most border regions, before economic development had set in, meant that it was impossible to satisfy their needs from purely local sources. Halting the western frontier at the Rhine, rather than on any of the other north–south rivers of western or central Europe – of which there are many, notably the Elbe – had another advantage too. Using the Rhône and (via a brief portage) the Moselle, supplies could be moved by water directly from the Mediterranean to the Rhine without having to brave wilder waters.

  The real reason why the Rhine eventually emerged as the frontier lay in the interaction of the motives underlying Roman expansion and comparative levels of social and economic development within pre-Roman Europe. Roman expansion was driven by the internal power struggles of republican oligarchs such as Julius Caesar and by early emperors’ desires for glory. Expansion as the route to political power at Rome had built up momentum at a point when there were still numerous unconquered wealthy communities around the Mediterranean waiting to be picked off. Once annexed, they became a new source of tribute flowing into Rome, as well as making the name of the general who had organized their conquest. Over time, however, the richest prizes were scooped up until, in the early imperial era, expansion was sucking in territories that did not really produce sufficient income to justify the costs of conquest. Britain in particular, the ancient sources stress, was taken only because the emperor Claudius wanted the glory.10 With this in mind, the limits of Rome’s northern expansion take on a particular significance when charted against levels of economic development in non-Roman Europe.

  Expansion eventually ground to a halt in an intermediate zone between two major material cultures: the so-called La Tène and Jastorf cultures (map 2). Some key differences in the general character of life distinguished the two. As well as villages, La Tène Europe had also generated, before the Roman conquest, much larger settlements, sometimes identified as towns (in Latin, oppida – hence its other common name, ‘the Oppida culture’). In some La Tène areas coins were in use, and some of its populations were literate. Caesar’s Gallic War describes the complex political and religious institutions that prevailed among at least some of the La Tène groups he conquered, particularly the Aedui of south-western Gaul. All of this rested upon an economy that could produce sufficient food surpluses to support warrior, priestly and artisan classes not engaged in primary agricultural production. Jastorf Europe, by contrast, operated at a much starker level of subsistence, with a greater emphasis on pastoral agriculture and much less of a food surplus. Its population had no coinage or literacy, and, by the birth of Christ, had produced no substantial settlements – not even villages. Also, its remains have produced almost no evidence for any kind of specialized economic activity.

  In the days when Kossinna’s assumptions ruled, and cultural zones were associated with ‘peoples’, it was traditional to equate the La Tène and Jastorf cultures respectively with Celts and Germani, but such simple equations don’t work. Zones of archaeological similarity reflect patterns of material culture, and material culture can be acquired; people aren’t just born with one set of weapons, pots and ornaments that they retain through thick and thin. While La Tène cultural patterns did originally emerge among some of Europe’s Celtic-speakers, and their Jastorf equivalents among certain Germanic groups, there was no golden rule that made it impossible for Germanic groups to adopt elements of La Tène material culture. And by the time Roman power advanced north of the Alps, some Germanic groups on the fringes of the Celtic world, particularly those around the mouth of the Rhine, had evolved a culture that was much more in line with La Tène than with Jastorf norms.

  The Roman advance ground to a halt not on an ethnic divide, therefore, but around a major fault-line in European socio-economic organization. What happened was that most of more advanced La Tène Europe was taken into the Empire, while most of Jastorf Europe was excluded.

  This fits a much broader pattern. As has also been observed in the case of China, there is a general tendency for the frontiers of an empire based on arable agriculture to stabilize in an intermediate, part-arable part-pastoral zone, where the productive capacity of the local economy is not by itself sufficient to support the empire’s armies. Expansionary ideologies and individual rulers’ desires for glory will carry those armies some way beyond the gain line; but, eventually, the difficulties involved in incorporating the next patch of territory, combined with the relative lack of wealth that can be extracted from it, make further conquest unattractive. A two-speed Europe is not a new phenomenon, and the Romans drew the logical conclusion. Augustus’ successor Tiberius saw that Germania just wasn’t worth conquering. The more widely dispersed populations of these still heavily forested corners of Europe could be defeated in individual engagements, but the Jastorf regions proved much more difficult to dominate strategica
lly than the concentrated and ordered populations occupying the La Tène towns. It was the logistic convenience of the Rhine–Moselle axis and cost-benefit calculations concerning the limited economy of Jastorf Europe that combined to stop the legions in their tracks. Germania as a whole was also far too disunited politically to pose a major threat to the richer lands already conquered. It was thus entirely appropriate that nineteenth-century German nationalists put the Hermann monument in the wrong place, since they also mistook his real significance. It was not the military prowess of the Germani that kept them outside the Empire, but their poverty.11

  As a result, the defended Roman frontier came by the mid-first century AD to be established broadly along a line marked by the Rivers Rhine and Danube. Some minor adjustments apart, it was still there three hundred years later. The consequences were profound. West and south of these riverine frontiers, European populations, whether Jastorf or La Tène, found themselves sucked into a trajectory towards Latin, togas, towns and, eventually, Christianity. Watching from the sidelines as neighbouring populations were transformed by Romanization, Germanic-dominated Europe north and east of this line never became part of the Roman world. In Roman terms, Germania remained the home of unreconstructed barbarians. The same label was used of the Persians in the east. However, this second major group of barbarians posed an altogether different level of threat.

  Persia and the Third-Century Crisis

  AT NAQS-I RUSTAM, seven kilometres north of Persepolis, lies the burial place of the famous Achaemenid Persian kings of antiquity, Darius and his son Xerxes, whose unwelcome attentions the Athenians and their allies fought off at the battles of Marathon and Salamis in 490 and 480 BC. Here, too, were discovered in 1936, inscribed in three languages on the side of a Zoroastrian fire temple, the proud boasts of a much later Persian king:

  I am the Mazda-worshipping divine Shapur, King of Kings . . . of the race of the Gods, son of the Mazda-worshipping divine Ardashir, King of Kings . . . When I was first established over the dominion of the nations, the Caesar Gordian [emperor, 238–44] from the whole of the Roman Empire . . . raised an army and marched . . . against us. A great battle took place between the two sides on the frontiers of Assyria at Meshike. Caesar Gordian was destroyed and the Roman army was annihilated. The Romans proclaimed Philip Caesar. And Caesar Philip came to sue for peace, and for their lives he paid a ransom of 500,000 denarii and became tributary to us . . . And the Caesar lied again and did injustice to Armenia. We marched against the Roman Empire and annihilated a Roman army of 60,000 men at Barbalissos. The nation of Syria and whatever nations and plains that were above it, we set on fire and devastated and laid waste. And in the campaign [we took] . . . thirty-seven cities with their surrounding territories. In the third contest . . . Caesar Valerian came upon us. There was with him a force of 70,000 men . . . A great battle took place beyond Carrhae and Edessa between us and Caesar Valerian and we took him prisoner with our own hands, as well as all the other commanders of the army . . . On this campaign, we also conquered . . . thirty-six cities with their surrounding territories.

  This is from the Res Gestae Divi Saporis (The Acts of the Divine Shapur); it encapsulates a strategic revolution, beginning in the third century AD, which transformed the Roman Empire.12

  Hitherto, resistance to Rome in the east had been led by the Parthian Arsacid dynasty, which had first established itself about 250 BC. The Arsacids ruled a world that could not have been more different from the forested homes of the north European Germani. The dynasty originated in Parthia and began to spread its dominion more widely over the Near East in the third century BC, quickly bringing under its sway territory from the Euphrates to the Indus. It thus encompassed a huge range of populations and habitats, but the dynasty’s heartland was soon to be Mesopotamia. Again unlike Germania, the history of this region had been punctuated by the rise and fall of great empires, not least the Achaemenid Empire of Cyrus, Darius and Xerxes. They had ruled not only the Near East, but also Egypt, western Turkey and the Fertile Crescent, and had even come within a whisker of swallowing Greece.

  The Parthian Arsacids had scored some early victories over the Empire in the late republican period, when Roman power had first penetrated so far east, most famously in the destruction of the army of Crassus, father and son, in 53 BC. But by the second century AD the dynasty’s capacity to mount serious resistance to Rome had diminished, and a succession of emperors won major victories on the Persian front. The latest came in the 190s, when Septimius Severus created two new provinces, Osrhoene and Mesopotamia, thereby advancing the frontier south and east. His victories threw the world ruled by the Parthians into crisis. Various members of the dynasty struggled for control, and some outlying regions threw off its suzerainty. As early as 205/6, rebellion began in the province of Fars beside the Indian Ocean. It was led by Sasan, the most important of the regional magnates, and was continued after his death by Shapur’s father, Ardashir I (reigned AD 224–40), the real founder of the Sasanian dynasty. In 224 and 225, he defeated two rival Arsacid rulers and established his control over the other regional magnates who had also broken away from Arsacid domination, before having himself crowned King of Kings in Persepolis in September 226.13

  As the Res Gestae Divi Saporis makes clear, the rise to prominence of the Sasanian dynasty was not just a major episode in the internal history of modern Iraq and Iran. Defeat at the hands of a succession of Roman emperors in the second century was a fundamental reason behind the collapse of Arsacid hegemony, and the Sasanians were able rapidly and effectively to reverse the prevailing balance of power. Ardashir I began the process. Invading Roman Mesopotamia for the first time between 237 and 240, he captured the major cities of Carrhae, Nisibis and Hatra (map 3). Rome responded to the challenge by launching three major counterattacks during the first twenty years of the reign of Ardashir’s son Shapur I (reigned 240–72). The results were as Shapur’s inscription records. Three huge defeats were inflicted on the Romans, two emperors were dead, and a third, Valerian, captured. Shapur proceeded to drag Valerian around with him, in chains, as a symbol of his own greatness – an image preserved for posterity in the great carved relief of Bishapur. After his death, Shapur had him skinned and tanned as a permanent trophy. Later in the century, a second Roman emperor, Numerianus, was also captured, but killed immediately: ‘They flayed him and made his skin into a sack. And they treated it with myrh [to preserve it] and kept it as an object of exceptional splendour.’14 Whether this was also Valerian’s fate, or whether he was kept on the floor or the wall, the sources don’t say.

  Nothing could better symbolize the new world order. The rise of the Sasanians destroyed what was by then more or less a century of Roman hegemony in the east. Rome’s overall strategic situation had suddenly and decisively deteriorated, for the Sasanian superpower, this new Persian dynasty, despite Rome’s best efforts in the middle of the third century, would not quickly disappear. The Sasanians marshalled the resources of Mesopotamia and the Iranian plateau much more efficiently than their Arsacid predecessors had done. Outlying principalities were welded more fully into a single political structure, while the labour of Roman prisoners was used for massive irrigation projects that would eventually generate a 50 per cent rise in the settlement and cultivation of the lands between the Tigris and Euphrates. This certainly began under Shapur, if not his father, and the resulting increase in tax revenues was coordinated by a burgeoning bureaucracy and directed to the maintenance of an at least partly professional army. Not for nothing did Shapur revive, in his diplomatic posturing towards the Romans, a claim to the old Achaemenid Empire in its entirety: he wanted not only Iran and Iraq, but Egypt, the Fertile Crescent and western Turkey as well.15

  Previously, Rome had operated in a context of dominance across all its frontier zones. Opponents might achieve local successes, but defeats could easily be reversed by mobilizing the Empire’s existing resources. Now, the rise of a rival superpower was a huge strategic shock. It had re
verberations not just for the eastern frontier regions, as Shapur’s record of sackings and captures recounts, but for the Empire as a whole. Not only did a much more powerful enemy have to be confronted on its eastern frontier, but the defence of all the other frontiers still had to be maintained. For this to be possible, a major increase in the power of the Roman military was necessary. By the fourth century, this had produced both larger and substantially reorganized armed forces.

  As we saw in Chapter 1, the Roman army of the early imperial era was divided into legions, each a small expeditionary army of 5,000-plus men, recruited exclusively from existing Roman citizens, with auxiliary units (infantry cohortes and cavalry alae) recruited from non-citizens. By the fourth century, the legions had been broken down into a greater array of smaller units. In some ways this formalized actual Roman practice, for individual cohorts of 500 men had often operated separately from the main body of their legion. In addition, the different classes of unit had been reorganized. Instead of legions and auxiliaries, the late Roman army was composed of frontier garrison troops (limitanei) and mobile field forces (comitatenses) gathered behind the three main frontiers: the Rhine, the Danube and the east. The field forces were more heavily equipped and a touch better paid, but the garrison troops were formidable too, not part-time soldier-farmers as they have sometimes been portrayed. For particular campaigns, they were often mobilized alongside the field forces. There was also much more specialization at the unit level: regiments of mounted archers (sagitarii), heavy artillerymen (ballistiarii) and plate-armoured cavalry (clibanarii, ‘boiler boys’) were employed. Overall, where Caesar had relied almost exclusively on the legionary footsoldier, there was now a greater emphasis on cavalry. Some of the heavy cavalry units were developed in direct imitation of their Persian counterparts, who had played a major role in the defeats of Gordian, Philip and Valerian. Nonetheless, in terms of numbers the late Roman army continued to be dominated by infantry, especially the mobile field forces; infantrymen, not dependent on the availability of animal fodder and able to move long distances while still fighting effectively, were actually more mobile in strategic terms.