by Woolf, Greg
But where to start? Persia was a dangerous enemy which had defeated Crassus and humiliated Antony, and did not seem to want further conflict. The tribes of northern Europe must have seemed an easy option: Caesar had conquered all Gaul in only eight years with as many legions. Could Britain and Germany offer anything other than easy victories? At first the victories did seem easy, and the armies of Drusus and Tiberius rolled around the Alps, campaigned up to the Danube, and across the Rhine as far as the Elbe. But rapid progress was deceptive. Conquered Pannonia rebelled in AD 6, and it took three years to restore order.
Almost immediately a Roman army of three legions was massacred in Germany in AD 9. The Varian disaster—named after the general made to carry the can—was a trauma that echoed through the history and literature of the last years of Augustus’ reign. The astrologer Manilius used it as an example of the terrible catastrophes foretold by comets. The actual defeat was a running battle lasting several days: the site was recently located at Kalkriese near Osnabrück and has been painstakingly reconstructed. It cost the Roman army nearly 10 per cent of its manpower. All territory east of the Rhine was abandoned. A half-built Roman city has recently been found at Waldgirmes, offering eerie witness to the sudden change of direction. A great new province had been planned, and construction had begun on a network of civil communities just like that created in Gaul after Caesar’s conquest and in Pontus by Pompey. Roman accounts, reflecting the official line, blame Varus for behaving as if he was in a conquered province, spending his time giving justice, imposing taxation, and dispersing his troops among native communities. But he was certainly following orders from the emperor. After disaster struck Rome pulled back to the Rhine, Waldgirmes was abandoned, and with it all the territory up to the Elbe. Conquest was never formally renounced, but it was not resumed in Augustus’ reign. Another imperial prince, Germanicus, visited the site of the disaster during the next reign but his campaigns were also—if less dramatically—unsuccessful. The north began to be quietly written off as ungovernable, poor, undesirable. Strabo, writing under the Emperor Tiberius, reported that Britain too would not pay the cost of its occupation.5 Appian, a second-century historian, went so far as to claim alien nations had begged to be admitted to the empire, but the emperors had turned them down.6 These were all lies.
For the emperors had much to gain from security, and there were easier routes to glory. Did Augustus ever realize that the real motor for the wars of Pompey and Caesar had been competition? And now there were no rivals. Emperors did not plan for peace, but they learned from their mistakes. The risks of failure never made up for the potential rewards offered by military expeditions. Much more could be achieved by diplomacy. And emperors soon found out how to massage the news from the frontier, playing up minor successes, suppressing news of reverses, claiming any victories for themselves, and blaming generals on the ground like Varus when things went badly wrong. The laziness of the Caesars was a very pragmatic response to the absence of rivals.
A World without History?
The choice of security over glory makes for unexciting history. Or so the senators of the imperial age affected to think. Court intrigues and imperial assassinations actually make for rather good drama. The histories written by the senators Tacitus and Dio, and the scandalous biographies of the courtier Suetonius and his late imperial successors, have inspired their share of racy novels and movies. But it is true that it is difficult to find a clear narrative in the political history of the first two centuries AD. Institutionally, culturally, and economically, there were slow changes.7 The citizen body expanded and with it Roman law stretched over more and more of the empire’s subjects: that process of assimilation continued long after the Edict of Caracalla.8 The greatest cities grew and acquired their complements of monuments. The rich grew richer, building great rural residences and endowing festivals, temples, theatres, and bathhouses in their native cities.9 Trade flourished across the urban network, and between the great ecological divides into which the empire was divided. All these changes were real, but few were visible to contemporaries, and they were not the subject of history as the ancients understood it.
There were gradual changes in the style of imperial rule too. The monarchical nature of the emperors’ rule became more overt. As the emperors ruled from their itinerant courts they seem to have gradually developed a preference for direct over indirect control, and a greater reliance on state officials rather than aristocratic former magistrates. Augustus had travelled widely, but few of his first-century AD successors spent long away from Rome. The expeditions of Trajan and the restless travels of Hadrian were in some senses optional, and Antoninus Pius who reigned from 138 to 161 spent most of his time in Rome. The situation began to change with Marcus Aurelius, who succeeded him until his death in 180. Marcus and his co-emperor Lucius Verus (161–9), and then his son and successor Commodus, who ruled until his assassination in 192, were all compelled to spend long periods of their reigns on the frontiers. So did all the Severan emperors who ruled Rome between AD 193 and 235. These necessary displacements were accompanied by the emergence of a new and more openly monarchical style. Away from senatorial sensibilities emperors could rule like the kings they had always been.
By the early fourth century there were up to four different courts at any one time, strung out along the northern and eastern frontiers of the empire. Wherever the courts rested for a few years—Trier or Antioch, Sirmium or Ravenna—magnificent palaces were created with great bathhouses, hippodromes, and reception areas. The empire came to be divided into four great prefectures, each headed by a praetorian prefect whose administration extended down into a growing number of provinces. Senators no longer played much part in the administration of the empire, and the Senate itself (or senates after Constantine created a second one in his new capital on the Bosporus) became peripheral to the political system. Ambassadors sought out emperors in the camps; law making had to be by edict rather than senatorial decree; consultation—even for form’s sake—was no longer practical. Emperors were away from Rome for years, and then decades. Constantius II, who with his brothers succeeded Constantine in 337, did not visit Rome until AD 357. Before that new order came about, however, the empire had to face a much more serious military emergency, one that in some senses lasted for two entire generations.
The Early Imperial Security System
Historians sometimes write of Rome as having a Grand Strategy,10 but there is no real sign that any such thing was ever planned or implemented. The deployment of the legions was accidental, the evolving product of incremental changes made in response to immediate needs. When expansion ended, Augustus’ campaigning armies had stopped in their tracks. Troops would be moved for imperial expeditions like Claudius’ invasion of Britain, or if they were needed to crush a rebellion or participate in a civil war. Over time the legions gravitated to the points of stress. Spain was far from the frontiers and relatively peaceful, and as a result the size of its garrison was progressively reduced. On the Danube and in the east troop numbers increased slightly, but always limited by the salary bill. The emperors knew where the troops were, how many they were, and what they were owed. But there is no sign they made use of this information to plan for anything but the short term.11
It is not always clear exactly where the armies were deployed in the early years of Augustus’ reign, except that they were kept out of Italy, where only the Praetorian Guard—made loyal through extra pay—were allowed in the capital. But a decade into Tiberius’ reign we happen to have a snapshot, from a passage in Tacitus’ Annales, of the locations of what were now twenty-five legions.12 They were concentrated overwhelmingly on the northern and eastern frontiers: facing across the Rhine and Danube, that is, and stationed along the long frontier with Parthia and its vassals. Only token forces remained in Spain, Africa, and Egypt. Many other provinces were effectively unarmed. Legions of heavy armed infantry formed the core of the early imperial army. They resembled the Republican armies in ter
ms of their equipment and battlefield tactics. Auxiliary units of cavalry, light infantry, missile troops supported them, alongside teams of engineers and other specialists. There were naval bases in the Mediterranean, and in time fleets were established on the major rivers. That pattern stayed more or less unchanged until the middle of the third century, although the number of legions increased to thirty-three and some were moved to newly conquered regions like southern Britain and Dacia. The total strength was always very small. At its height the early imperial army numbered less than 200,000 legionaries and perhaps as many support troops, to protect and control an empire of between 50 and 100 million inhabitants.
Keeping the army small was a financial necessity given the huge share of the imperial budget it consumed. This meant it had to be highly efficient. The campaigning armies of the late Republic and the reign of Augustus had marched and camped in strength, but a different disposition was needed for their new roles. The logic of the imperial frontiers was all based on establishing a communications advantage over its opponents. Little by little the frontiers became a dense network of bases—some very small—signal stations, barriers, control points, and, most important of all, roads. Hadrian’s Wall provides an excellent example of the kind of system that developed in the second century, but the ditches and ramparts that so impress us today were among the latest and least vital components of a frontier system. A precious collection of letters from Vindolanda reveals the collection and processing of information on what was happening beyond the frontier; the management of provisioning; the constant redeployments of soldiers along the frontier; and communications back into the province.13 Signal stations ran down the coasts watching for raids by sea. Groups of scouts operated far north of the wall, and local leaders were cultivated with gifts that Romans called subsidies. A slightly different system of signal stations and forts passed news on barbarian movements up and down the upper German Limes, and in the pre-desert of North Africa military installations were different again. Physically the frontiers developed in a piecemeal way, adapting to local circumstances not a central model, but the guiding logic was the same.
The vast majority of military units were based on the frontiers. Yet soldiers were ubiquitous in the empire. Detachments provided protection for provincial governors and procurators, for messengers and tax collectors, for movements of grain and cash, for the managers of imperial mines and quarries with their workforces of slaves and criminals, and for the authorities of the larger, more unsettled cities. Centurions in particular acquired a whole range of functions we do not normally associate with the military. They acted as district officers in the northern provinces, can be found on detachment organizing provisioning and as the most recognizable representatives of Roman government depicted in the New Testament. Particularly trusted soldiers served as beneficiarii consulares, effectively aides de camp to governors. The early empire had no civil service, and there were some jobs that it was impolitic to entrust to imperial slaves and freedmen.
Fig 17. Hadrian’s Wall
Imperial propaganda proclaimed that the soldiers protected the provinces. That picture is only half true. The legions were also the emperors’ ultimate weapon against both provincial rebellions and aristocratic usurpers.14 The mass demobilization of Roman soldiers at the end of the Triumviral period had been driven by financial and political priorities. Armies were dangerous, unpaid ones doubly so. Now they would be composed of career soldiers who served for twenty or more years, loyal to the emperors, not their commanders.15 On retirement the emperors provided each man with a substantial bonus, so long as he had proved himself loyal. Commanders, drawn from the senatorial and equestrian orders, came and went. It was the centurions, risen from the ranks, who provided continuity of command and military expertise. Ceremonial was deployed to bind the soldiers to the imperial family. Army units celebrated imperial birthdays, and worshipped the emperors along with the signa, their standards. A third-century calendar from the eastern frontier post of Dura lists endless holidays marking the anniversaries of imperial family members, some long dead. Emperors and their sons took care to visit the legions, and even commanded them when it was safe to do so.
Mostly the system worked. Civil wars only broke out in 68 and 196 when entire dynasties had been extinguished. A few rebellious generals discovered to their cost the depth of loyalty the legions felt to the imperial family of the day.16 That loyalty meant that the legions could also be deployed against provincial rebels. During AD 69 the legions of the Rhineland were deployed first against Vindex, a senator from southern Gaul who had rebelled against Nero, and then against the Batavians of the lower Rhine who had tried to use the Roman civil war that followed his death as an opportunity to secede. The legions were in principle recruited from Roman citizens, but Italians rarely joined up after Augustus’ reign. The main sources of recruits were first the Roman cities of the inner provinces and later the camps themselves. One sign of the success of the emperors’ investment in maintaining the loyalty of the troops (and perhaps too of the socialization effects of long service) is that legions almost never made common cause with neighbouring provincial populations. Troops recruited in Gaul and Germany were content to be deployed against British, Gallic, and German rebels, and the army of Numidia to march against African usurpers.17
Mostly, however, the soldiers inhabited a world of their own. The larger camps of northern Britain, the Rhineland, the Danube provinces, and Africa eventually came to resemble cities, equipped with monumental walls and gates, stone-built amphitheatres, bathhouses, and shrines. Formally soldiers could not marry and camps were organized in barrack blocks arranged in precise parallel lines, but the artefacts and clothes found in them shows there were women and children in these communities too, as well as in the informal villages called canabae that grew up alongside them. In Syria and Egypt soldiers mostly lived in cities in any case. Documents from Dura show them marrying and buying land and in general assuming the sort of roles in local communities that their relatively good pay and excellent connections could secure them.18
The Roman Empire had no Grand Strategy, but it nevertheless developed a frontier system quite like those of many other tributary empires. The most common point of comparison is China’s Inner Asian Frontier, the limit between the areas controlled directly by Chinese officials and a great periphery within which subject nations shaded out into barbarian allies and enemies.19 China, like Rome, enjoyed some technological advantages over its neighbours, although in some periods there was something of an arms race as China sought to prevent technology transfers to the barbarians. China, like Rome, was able to provision and supply its troops from an intensely farmed and taxed hinterland. The Chinese too deployed a mixture of linear barriers and garrisons of regular soldiers with irregular allies, and they too sought an information advantage over their opponents. The information system extended deep into the provinces, to the imperial court or courts. It was not Grand Strategy that preserved either empire, but the tactical advantages given by information superiority.
Map 5. The third-century crisis
Crisis on the Frontiers
The Roman system had, naturally, its weaknesses too. One consequence of depending on an infantry army based at the edge of empire was that it was slow to respond to disasters in the interior. Roman troops were generally successful against provincial rebellions during the first two centuries AD because most rebellions occurred relatively near the frontiers, and the rebels were usually stationary and had no fortifications. Order was generally restored within months. The Jewish war lasted as long as it did because the Jews possessed fortresses. Another problem was that more mobile enemies, once they broke through the frontier, could outrun Roman armies. When the frontiers did collapse, as they did in the third century, and raiding parties penetrated as far as Athens and Ephesus and Tarragona, they found rich cities with no defenders and often no functioning defensive walls. Civic populations learned the lesson. During the late third and fourth centuries, city a
fter city built defensive circuits, sometimes dismantling earlier monuments to create safe zones in the middle of once extensive cities. One third-century emperor, Aurelian, actually built walls around the centre of the city of Rome. One of his predecessors, Gallienus, had also begun developing a more mobile army, one based on cavalry, which could act as a rapid response force. The use of troops of this kind, alongside the legions, became more and more evident in the changed conditions of war on the northern frontier. Constantine too was credited with an enlargement of their role. Meanwhile, at the eastern end of empire Romans and Persians were both developing armies based on heavy cavalry. Where urban fortifications were also improving as fast as techniques of siege warfare, the military landscape came to look more and more medieval, a world of knights and castles amidst a landscape of peasant villagers.