No coherent analysis of the causes of war in the imperial period is possible because of our flawed or inadequate source material.99 But it is worth asking if we can overcome this problem by taking a wider view based partly on comparative material derived from the discipline of defence analysis. On this basis war and military dispositions may perhaps be explained in terms of the evolution of an empire-wide strategy and an overall response to long-term strategic, tactical and diplomatic concerns, based on what have been described as ‘scientific frontiers’.100 These were modified occasionally by individual emperors, who were essentially therefore taking rational decisions, which to some extent depended on perceived wisdom and practice, and amounted to virtually a common policy, at least in certain areas of the empire.
Indeed, this theory suggests that Roman strategy was successively modified in the light of experience and changing circumstances. The Julio-Claudians maintained a ‘hegemonic’ empire, in which strategically situated forces could be concentrated where necessary, supported by the forces of friendly kings. From the late first century onward there emerged the idea of preclusive defence, with sharply delineated frontiers, defended by forces in fixed locations, which dealt with hostile activity outside the frontiers. This was a ‘territorial’ empire, which achieved the maximum influence for Roman power with an economy in the use of force. In the third century, as the empire came under greater threat from external forces, the Romans resorted to ‘defence in depth’, using self-contained strongholds with mobile forces deployed between or behind them.101
If true, this theory could have serious implications for how we view the causes of war in the Roman world. Although emperors doubtless had differing levels of interest in strategic and military concerns, it would certainly be wrong to assume that the Romans did not have a judicious approach, and that they did not review the military situation of the empire in the context of what they had learned about other peoples. Indeed, we can detect some degree of rationality and long-term thinking in the changing disposition of the legions.102 But there are serious objections to the theory of a ‘grand strategy’, and it is difficult to believe that the Romans ever thought this way.103 First, they simply lacked the intelligence information required in order to develop such far-sighted or proactive policies - though, as with most governments in charge of a large army, there will have been some strategic planning. They were also defective in adequate and up-to-date geographical knowledge about areas on the periphery of the empire.104 Second, emperors were usually inexperienced in war, they had no army high command or highly experienced long-term military advisers, and no secretary of state for defence who could coordinate a coherent empire-wide strategy. In addition, there was no permanent mechanism for diplomatic contact or diplomatic representation, no permanent officials charged with foreign policy, and no specialist practitioners in negotiation. It is worth remembering that Augustus’ last advice to his successor on military strategy was simple and uncomplicated.105 Third, in reality Roman frontier zones were not similar in nature or purpose, or seemingly coordinated. Archaeological evidence, which is important because literary evidence is sketchy, is much disputed in respect of the identification and significance of forts, walls and roads.106 Even in the case of one of the great linear constructions, Hadrian’s Wall, there is a school of thought that it was not primarily a defensive barrier, but a means of controlling the movement of peoples and traffic in the vicinity of Roman territory.107 There is indeed little sign of any concerted attempt to achieve consistent or coordinated long-term objectives in dealing with foreign peoples across the entire empire. As we have seen, decisions on war and peace were taken by individuals often for immediate reasons in the light of local condi-tions.108 In the main, emperors were shrewd and rational judges of their self-interest, and tended towards a relatively passive approach, in which they reacted to events and opportunities as they appeared. Finally, it is wrong to assume that the prevailing view in Rome was the need to defend the empire against threats from hostile neighbours. No ancient commentator
Indicates that the Romans thought in this way; they had no word in Latin for ‘frontier’ in the sense of a formal barrier or fortified line. Instead, with a self-confident belief in their military superiority, they probably saw no need for long-term planning. Furthermore, the designation of Roman territorial control in no way ruled out the absorption or conquest of peoples beyond.109
Finally, the pattern of Roman warfare and the deployment of the legions can shed some light on the causes of war and wider strategic concerns. After the sustained warfare and conquests of the Augustan era there was apparently some fighting in the reign of nearly every emperor who ruled for more than one year, apart from Gaius and Titus. Of course the significance of this warfare varied, but even the quelling of a revolt could require the commitment of large numbers of troops, and the Jewish revolts between 66 and 70 and 132 and 135 amounted to major campaigns.110 It is clear that until the later third century the Romans were aggressive and militarily self-confident, and this often involved the domination of other peoples and their resources.111 The success of the army during this period in consolidating and extending Roman power probably made further warfare more likely, since the Romans could not tolerate any disruptive or provocative activity on the periphery of their territory.
Nevertheless, the extent of warfare was relatively limited in geographical terms, and the large majority of Roman soldiers at any one time would not be engaged in serious fighting. The Roman peace was therefore genuine, in that for long periods many provinces saw little military action. Indeed, despite the degree of military activity over three centuries and the Roman emperor’s military trappings and complete control of the army, he did not become a warlord or sustain his control by routine warfare. There was no clear-cut imperial dynamic towards war. The Romans were not addicted to warfare and did not seek to sustain their empire by persistent conquering or continual expansion, though its inner logic dictated that no territory be surrendered in order to preserve the integrity of government.
The deployment of the legions at first indicated the main direction of Roman military advance, in Spain, on the Rhine and the Danube, in Britain, and in the east. Later there was an increasingly heavy concentration on the Danubian provinces as Rome tried to deal with turbulent, unpredictable northern tribes. Finally, there was a further shift of resources to the east to extend and then protect Roman interests between the Euphrates and the Tigris in the simmering conflict with the Parthians and their formidable successors, the Sasanids (Figures 1.1 and 1.2).112 The first significant signs of a changing situation appear in the long wars which Marcus Aurelius fought in the north initially to protect Roman provinces against German tribes invading across the Danube. By the mid-third century the Romans were involved in virtually continuous warfare, but generally not at times or locations of their choosing. They now fought defensive wars to preserve
Figure 1.1 The disposition of the legions in AD 14
Figure 1.2 The disposition of the legions in AD 200
The status quo and avoid the loss of territory long regarded as Roman. In 260 the emperor Valerian was captured by the Persian king Shapur as he tried to defend Mesopotamia from invasion; he was to die in captivity. Then, probably in 274, the emperor Aurelian decided to abandon the province of Dacia, moving soldiers of the garrison and the civilian administration to the south bank of the Danube. In the later third century, as the empire’s strategic position worsened, emperors were committed to fight further wars in order to preserve Roman lands and resources, and the vast cost of this military effort caused even more hardship for the declining body of taxpayers. In the end, wars were fought largely to regenerate imperial power and sustain the memory of Rome’s greatness. Even in the fifth century, Rutilius Claudius Namatianus, a poet of Gallo-Roman family and a high-ranking official (he had been Prefect of the City in 414), writing after the sack of Rome by Alaric and the Goths in 410, predicted a return of imperial glory: ‘Fortune/which is cruel today will be kind tomorrow./Let your law extend to all the known world;/it will not die.’113
World History
