SCOPE AND AIMS

this study is concerned with the foreign relations of the Roman empire during late antiquity, defined here as the period from the early third to the early seventh century ad. It is not, however, a general history of late Roman foreign relations. In the first place, it pursues a particular theme within that field – the role of information. And secondly, it focuses on late Roman relations with two particular regions – Sasanian Persia in the east, and the areas adjacent to the empire's northern Continental frontier, occupied by a number of different peoples of Germanic and central Asiatic origin during the course of late antiquity. At the same time, this study deals with much more than just military and diplomatic affairs: the particular questions it pursues entail consideration of the broader context within which relations were played out, notably the socio-cultural character of the relevant frontier regions, and the differing levels of organisational complexity among the empire's neighbours.

Numerous studies have been devoted to elucidating various aspects of the history and conduct of late Roman foreign relations, but the role of information has received little systematic attention. Yet there can be no doubt as to its importance.

no treatment of late Roman foreign relations would be complete without some consideration of the frontier regions within which those relations were played out. In the case of this study, however, an investigation of the relevant frontier regions is especially vital because their character exercised an important influence on the availability of information. The Roman empire as a whole encompassed considerable diversity, both environmentally and culturally, and this is particularly apparent in the contrasts between the frontier region shared with Persia in the east, and that (or rather those) along the northern bounds of the empire. These differences form the focus of this chapter; their full significance will become apparent at a later stage (see Chapter 5).

THE EAST

The formal political boundary between the Roman and Persian empires was subject to some variation during the course of late antiquity, but apart from a brief period in the early seventh century, the southern half of its course always lay within the open region of northern Mesopotamia. The northern half of the boundary proceeded across the mountainous territory which lay between the Taurus range and the Black Sea, though the existence of the kingdom of Armenia during parts of the first century and a half of Roman–Persian relations meant that the two empires did not always have a common boundary in this area.

the preface is traditionally the place where one offers a justification for the writing of a book. In this case, however, the question was not whether the subject was one worth writing about, but rather whether it was feasible, given the limitations of the available sources. The role of information in Roman foreign relations during late antiquity is a field of enquiry whose importance should be self-evident, yet, perhaps because of the apparent dearth of relevant material, it has not previously been investigated in a systematic manner. I hope to have shown that greater progress can be made than might otherwise have been thought possible, even if many pertinent questions have had to be left without satisfactory answers.

It will be readily apparent from the footnotes how much this book owes to the labours of numerous late Roman and early Byzantine scholars, especially in recent decades and in the elucidation of the literary sources. I have endeavoured to acquaint myself with as much of the relevant modern literature as possible, but in so vast a field I am bound to have overlooked items; some publications have appeared too late for me to use, notably the volume on Byzantine Diplomacy edited by Simon Franklin and Jonathon Shepard which includes a number of papers dealing with late antiquity.

the concerns of this chapter may usefully be introduced by consideration of three episodes, each, as it happens, falling within a period of less than a decade during the middle of the fourth century and each recounted by the historian Ammianus Marcellinus.

The first concerns the activities during the mid-350s of the praetorian prefect of the east, Strategius Musonianus. He is reported to have investigated Persian plans through the agency of spies (speculatores), from whom he and an associate learned (aperte cognossent) that the Persian king Shapur II was currently engaged in fierce fighting with hostile peoples on a distant frontier of his empire. On the basis of this information Musonianus initiated secret negotiations with a Persian official, in the hope that these difficulties would incline the Persians towards a formal peace settlement with the Romans and put an end to the costly but inconclusive warfare of the previous two decades (xvi.9.2-3).

In the event, Musonianus' diplomatic initiative proved not only abortive, but positively counter-productive, leading on to the second episode. The Persians concluded from Musonianus' initiative that the Romans themselves were in difficulties, and since Shapur had been able, by early 358, to bring his own war to an end, he decided in turn to try to exploit Roman problems and sent envoys to demand territorial concessions as the price for peace.

in his inaugural lecture at the London School of Economics in 1967, entitled ‘1914: the unspoken assumptions’, the distinguished historian of modern Europe, James Joll, drew attention to the need for those investigating the origins of the First World War to explore the underlying presuppositions which influenced decision-makers in the years and months leading up to August 1914 – ‘to reconstruct, so to speak, their ideological furniture’. Among other things, this would involve giving attention to the values and beliefs inculcated in the upper classes by the educational systems of the Great Powers, and to intellectual currents, such as Social Darwinism, exercising influence at a popular level. Clearly, a concern with ‘unspoken asumptions’ is a desideratum in the study of foreign relations in any period. As Joll readily acknowledged, however, it is no easy task to make connections between these sorts of areas and the conduct of foreign policy. If that is the case for the modern historian, with a mountain of letters, diaries and memoirs at his or her disposal, how much more difficult, if not impossible, for the historian of antiquity, for far more elementary matters such as what late Roman government knew of the geography and socio-political organisation of neighbouring peoples. Nevertheless, questions of this sort clearly need to be considered and some attempt made to answer them, even if rendered far from satisfactory by the nature of the available sources.

SASANIAN PERSIA

Organisational character

in the mid-220s the Parthian Arsacid dynasty, rulers of a state which for the past three centuries had been the Roman empire's largest eastern neighbour, was overthrown by the revolt of one of the nobility, Ardashir, lord of Persis (Fars). During the preceding years Ardashir and his father had exploited the turmoil arising from Roman invasion and disputed succession within the royal family to expand their domain to a point where Ardashir was able to challenge for the rulership of all Persia. The success of that challenge marked the establishment of the new Sasanian dynasty, an event which was to have fundamental repercussions for the Roman empire. In place of the increasingly weak and fragmented state with which it had dealt in the second century, the empire soon found itself confronted by a regime intent on controlling more closely the territories it had inherited and enlarging them.

Given the experience of the Parthians, it was clearly in the interests of the new dynasty to try to restrict as much as possible the power and independence of the other noble families in Persia and to expand centralised royal control. There can be no doubt that overall the Sasanians achieved greater success in this realm than the Arsacids had done. Indicative of their aspirations is the more pronounced royal support of the Zoroastrian religion, which was no doubt seen as possessing unifying potential while also serving as a counter-weight to the nobility.