The Parthians knew that the Roman Empire was large and very strong. Rome itself was so distant that it was unreachable by any Parthian army, but the Parthian king’s heartland in the valleys of the Euphrates and Tigris were within the reach of Roman armies. The Romans made it very clear that they did not consider the Parthians as their equals. No Roman emperor ever met a Parthian king in person, or acknowledged him as his peer. A long succession of Parthian kings’ sons went to Rome as hostages and were educated in the imperial household, while numerous challengers for the throne, along with their followers, were accepted into the empire. There was no similar traffic in the other direction. Many Parthian kings had a tenuous hold on power, a situation the Romans exploited through supporting and sheltering potential rivals. The border with Rome was also not the only threat faced by the king, for there was the ever-present risk of internal rebellion, while frontiers to the north and east faced dangerous and aggressive peoples. In the north-east, the nomadic Alans troubled both Parthia and the Roman provinces over a long period. By comparison it was far easier to maintain peace through negotiation and treaty with the Roman Empire.
The Alans periodically threatened Cappadocia, and were just one of the numerous peoples the Romans faced along their borders. Like the Parthians they were famous for their cavalry, some of them heavily armoured and lance-armed like the cataphracts and others skirmishers. Although they used composite bows, they were seen as less effective archers, and their armies lacked the discipline and organisation of the Parthians, but remained dangerous and were vigorous raiders. They were a Sarmatian people, and other similar groups lived around the Black Sea and along parts of Rome’s Danubian frontier.34
Other European peoples relied mainly on warriors who fought on foot, with only small numbers, often noblemen, fighting from horseback. There were many different tribes, clans and kingdoms living near the frontiers of the empire, such as Dacians on the Danube, Germanic peoples on the Danube and on the Rhine, and the Britons. For all their differences in language and culture, they shared a common lack of political unity. Even tribes seen as a distinct group by the Romans were often divided into factions supporting different leaders. Competition within tribes was frequently violent, and hostility to neighbours common. Men like Sulpicius Galba and Julius Caesar would have noticed only minor differences between the tribal societies they had encountered and the ones living outside the empire in the first and second centuries AD.
Chieftains, kings and princes alike kept a following of full-time warriors in their household. Tacitus says that it was common for restless German warriors whose tribes were at peace to go and take service in the following or comitatus of leaders of another people, and talks of how chieftains rewarded their bravest warriors with gold, weapons or the gift of a horse. These household warriors or comites displayed and maintained a man’s power, and their numbers and fame were a visible sign of his status. Effectively professional warriors, they were well equipped by the standards of the tribes, skilled with their weapons and highly motivated. Tacitus says that chieftains vied to prove their prowess to their followers, while the warriors would be shamed if they did not match their courage. Augustus formed a special bodyguard of German tribesmen because they were famed for their loyalty. Disbanded after AD 9, it was reformed under his successors. The bond between chieftain and household warriors was often as strong among other tribal peoples. They were the pick of a tribal army, but they were relatively few in number. A range of sources give the impression that even a king rarely mustered more than a few hundred warriors in his comitatus.35
Many tribes were capable of forming large armies, but the bulk of these consisted of free men able to provide themselves with weapons and willing or obliged to gather. These were farmers and herdsmen rather than dedicated warriors, which is not to say that they were unskilled. In such warlike cultures, most men grew up accustomed to weapons and the possibility of violence. Yet their equipment was likely to be basic. Few would have body armour, fewer still helmets. Swords were likely to be the preserve of the noblemen and their comites, and even among these armour was probably relatively rare. The majority would rely on spears or javelins and have only a shield for protection. Some might use slings or bows, but these longerrange missiles were no more than support for the mass of warriors fighting in close order. The contrast with the Roman army is marked, where the rank-and-file legionaries and auxiliaries wore armour and helmet, carried a shield, and each wielded a well-made sword. This was the equipment only a chieftain or leading warrior could match.
Large tribal armies were slow-moving and clumsy. It took some time for them to muster, and it was no coincidence that Roman armies ravaging tribal lands were usually faced with an enemy army only after they had begun to withdraw back to the frontier. Command and control was rudimentary, especially since there might well be several leaders rather than a single overall commander. Supply was left to individual warriors – or often their wives and families, who followed them when the army gathered – and this meant that after a couple of weeks they would have consumed the food they had brought and be forced to disperse. Tacitus singled out the Chatti as unique among the Germanic peoples for having an organised system to feed their warriors, and obeying commanders and submitting to a measure of discipline. ‘Other Germans may be seen going to battle, but the Chatti go to war.’36
It was not a system suited to prolonged warfare or to large-scale attacks over long distances. Big armies gathered to defend their own territory against attackers or sometimes to challenge neighbours for dominance in short campaigns in spring or summer. Some intertribal conflicts led to the break-up or displacement of a group, but most activity was smaller-scale and likely to consist of the raiding common in so much of the ancient world. The comitatus of a chieftain were ideally suited to this, and successful expeditions gave the leader a chance to reward followers. Several chieftains might combine to gather a larger band, bolstered by volunteers from the wider community drawn by the prospect of adventure and loot. Aggressive raiding created hatred and sparked reprisal raids from the victims, but if it was sufficiently successful it deterred others. As we have seen, Caesar tells us that the tribes tried to create a strip of depopulated land around their own territory to display their strength and warn off aggressors.37
Sometimes charismatic and successful leaders emerged, able to unite their own tribe and even persuade or force others into confederation. Arminius of the Cherusci and Maroboduus of the Marcomani were examples of this, each uniting other tribes for a while. The former based his rule on defying Rome, the latter on avoiding conflict with the empire and seeking Roman recognition. The armies they led were larger and more tightly controlled than the usual tribal forces. Their warriors were also better equipped – Tacitus claimed that they had a plentiful supply of Roman equipment and adopted Roman-style tactics. Velleius Paterculus credits Maroboduus with an army of ‘seventy thousand infantry and four thousand cavalry’ which he was ‘steadily preparing by exercising it in constant wars against his neighbours’. He and Arminius were exceptionally successful, and in time they became rivals, the resultant conflict leaving Maroboduus fatally weakened. Soon afterwards he was driven out by another challenger and ended his life in comfortable exile within the empire. Arminius was murdered by chieftains who resented the dominance of one man, and in neither area did a similarly strong leader appear for several centuries. The power of such warlords was precarious and rarely outlived them.38
In Julius Caesar’s day Burebista united the Dacians and created a formidable kingdom, but this crumbled when he died around the same time as the Roman dictator. It was not until more than a century had passed that a similarly strong king emerged. This was Decebalus, whose rule extended beyond his own people to include neighbouring Sarmatians and Germanic groups like the Bastarnae. Dacia was heavily fortified during these years, with forts and walled towns defended by stone ramparts employing a mixture of local, Gallic and Hellenistic techniques, eventually combined with Roman
engineering supplied by deserters and the experts loaned to the king as part of his treaty with Domitian. More deserters served him as soldiers, adding to the large number of men kept permanently under arms. Decebalus proved a dangerous opponent who invaded and plundered the Danubian provinces, inflicting several serious defeats on the Romans. Yet leaders of such power were rare, and most of the time along the frontiers in Europe and North Africa even the important tribal leaders wielded authority that was far smaller in scale and had far more modest forces under their command.39
ATTACK AND DEFENCE
Under Augustus poets sang of imperium sine fine – power without limit or end – and this dream lived on for centuries. To expand Rome’s power was felt to be an admirable thing by emperors and aristocrats alike, although, as in earlier periods, this could be achieved without annexing territory. Yet it was not the only or even the first priority of his successors, nor was it generally felt to be an urgent and immediate need. Some emperors ordered or led aggressive wars and sought the glory of new conquests. Occasionally this sprang from a personal desire for fame or a longing to match the achievements of the great conquerors of the past, both Roman generals and Alexander of Macedon. More often the quest for personal glory came from the need felt by insecure rulers and ones without any past military achievements to prove themselves. Yet emperors who failed to expand were not automatically unpopular or condemned for this reason alone, as long as it was felt that Roman military might and dominance remained unimpaired. Modern scholars often present expansion and defence as mutually exclusive, but this is artificial. Rome’s imperium could only increase if the Romans preserved what they already had, which meant that control of existing provinces was always at least as important. Allied states needed to be kept within Rome’s sphere, and the Romans could not afford to let these or the directly governed provinces be destabilised by rebellion or attacks from outside. Augustus’ reign saw as much consolidation as conquest.40
The Roman Empire at his death had borders stretching for thousands of miles across all three of the known continents in the world. Beyond lived a vast array of different societies and groups, some large, some small, but never united, so that it was very rare even for a few neighbours to act in concert. Rome did not face one or more rival great powers whose interests inevitably conflicted with its own, nor any potential opponent capable of matching her economic and military resources, still less with any realistic hope of crippling or destroying the empire. This may not always have been apparent to all their neighbours, aware only of the imperial province nearest to them. Under Augustus, the warriors of Queen Candace of Ethiopia attacked the Roman province of Egypt at least twice. The first Roman counter-attack achieved little, but after a second, deeper invasion the queen was willing to negotiate for peace. When her ambassadors were told by the prefect of Egypt that they must go to Caesar Augustus, they protested that they did not know ‘who Caesar was or where they should have to go to find him’, and were given an escort to the emperor, who happened to be on the island of Samos when they reached him.41
No one equalled Rome’s strength, but then no one ever faced the full might of the empire for there were always other wars – or the fear of other wars – elsewhere. After AD 9 Arminius faced eight out of the twenty-five remaining legions. He was unable to stop them from marching through the tribes’ lands, destroying farms and killing or seizing cattle, and then returning to their bases on the Rhine. They in turn were unable to break his and his allies’ determination to fight on, and eventually Tiberius called a halt to major attacks east of the Rhine. Most of the Roman troops remained in place on the west bank of the river, but their commander, his adopted son Germanicus, was soon sent to Syria and the eastern frontier, the latest in a succession of imperial princes despatched to negotiate with the Parthians.
In spite of the enthusiasm of poets, Augustus did not attempt to conquer the Parthians, and avoided major military confrontation with them. Instead he negotiated, but these talks always occurred alongside a display of Roman might. Armies were massed and marched to the borders of the empire, led by the princeps or a member of his family, so that diplomacy rode on the back of the threat of force. The lost eagles were returned and installed in the Temple of Mars Ultor, and a triumphal arch built to celebrate the submission of the Parthians. Augustus presented Parthia – and for that matter India and Britain on the basis of embassies sent to him – as part of Rome’s imperium.42
This pattern of diplomacy backed by the threat of force was repeated under Tiberius and for most of the first century AD, save that after Germanicus such negotiations were usually handled by a legate rather than a member of the imperial family. Only under Nero did these peaceful relations break down, when the Parthian King Vologases I intervened in Armenia and placed his brother on the throne. This led to a war fought by substantial forces on both sides, but the focus remained on Armenia. The Romans did not launch an invasion deep into Parthia’s heartland, nor did the Parthians make a serious effort to overrun the Roman provinces. An early Roman advantage was lost, when the legate of Cappadocia was defeated and surrendered, but then regained, allowing them to negotiate from a position of more strength. The result was a compromise, with the newly installed king travelling to Rome to accept his crown from Nero. If this was partly a sham, since the Romans had not chosen the man but been forced to accept him, the willingness to submit to this ceremony was a public demonstration of respect for Rome’s supremacy.
Throughout the first century AD the balance of power favoured Rome. Most Parthian kings were not sufficiently confident in their own position to risk confrontation with their powerful neighbour. A war with Rome was likely to be difficult, and ran the chance of serious defeat which might well destroy a ruler’s credibility. Their fears were reinforced by the Roman skill at harbouring and exploiting exiled members of the royal family. There was a consistent desire to retain influence in Armenia, ideally by having a relative as king, but ambition did not stretch much beyond this – or if it did, was restrained by respect for Roman power. During the civil war following the death of Nero, the Parthian monarch did not attempt to exploit Roman weakness, but pledged himself to peace and even offered Vespasian troops to support his bid to become princeps. This was declined, but it did make it easier to transfer some of the forces in the eastern provinces further west to fight in the civil war.43
Throughout the first century AD the Romans maintained substantial garrisons in the eastern provinces, with legions in Syria, and later Cappadocia as well as Judaea after AD 70. These units and their auxiliaries were not solely concerned with defence and deterrence of the perceived Parthian threat. As we have seen, the Syrian army made a succession of interventions in Judaea, and was also employed to enforce Rome’s will with allied kingdoms, annexing several of them. Nero’s war against the Parthians was essentially another example of this, fought to keep Armenia as an ally within Rome’s sphere of influence. Vologases I’s intervention was part of his wider efforts to gain control of several kingdoms in the area. According to Tacitus, Armenia was ‘once the property of his ancestors’ and now in the hands of a usurper. His actions were not intended to provoke Rome, and at first he was conciliatory, withdrawing his troops and giving hostages – Tacitus hints that this was a way of removing distrusted aristocrats – when threatened with the usual mixture of diplomacy backed by force. Only his unwillingness to see his brother stripped of his crown or installed by the Romans led to a renewal of open warfare, and in the end he compromised on the second point.44
The Romans had reasonable knowledge of Parthia, and there were frequent diplomatic exchanges, with Parthian embassies going to the provincial legates and to Rome. Centurions were the usual couriers for Roman letters and were able to negotiate and report back – a sign of the important roles given to this grade of officer. One of them happened to be at Vologases’ court on another errand when the king was asked to hand over the hostages and so dealt with this matter as well. There were several moments of ten
sion and posturing by both sides which did not lead to war, but it is hard to see any trace of a deep-seated Roman desire to conquer this rich and powerful neighbour, and instead the Augustan claim to be dominant was preserved. This was reinforced by a gradual increase in the size of the garrison in the east. Roman outposts were established further and further forward, and when Trajan annexed Arabia, it was just the latest allied kingdom to be taken under direct rule.45
In the second century AD both powers became more aggressive. Trajan’s full-scale invasion marked a fundamental break with the cautious diplomacy of the past. While there may have been some provocation and pretext for this, the sources suggest that his main motivation was a quest for glory. The attempt to conquer failed amid widespread rebellion, and the new provinces were abandoned by Hadrian, although it is clear that Roman-backed allied rulers remained in power over a wide area. A generation later, an ambitious Parthian king began to recover some of this territory, perhaps encouraged by the reluctance of the elderly Antoninus Pius to authorise aggressive military action. In AD 161 the Parthians invaded Syria but after early successes were driven out, and in the Roman counter-offensive their capital of Ctesiphon was sacked for the second time. The Romans established some bases beyond the Euphrates and imposed peace on Parthia, but did not attempt wider annexation.
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