The coming to power of the Sassanian Dynasty in Iran in AD 224 opens a new chapter in the struggle for hegemony in the Near East. Till then, Rome’s fortunes had fared reasonably well in its perennial conflict with the Parthians. The ignominy of Crassus’ defeat at Carrhae was little more than a schoolboy jingle: ‘Carrhas Crassi clade nobiles’ (Carrhae whose name was renowned by reason of her defeat of Crassus) and it certainly did not compel commanders like Corbulo to regard the Euphrates as a sacred barrier to ambition and fame. Though Trajan’s sweeping conquests at the beginning of the second century in Mesopotamia were mostly abandoned by his immediate successors, Roman power gradually reasserted itself east of the Euphrates as the century progressed. The Parthian Wars of Lucius Verus in 165 saw the formal incorporation of the Euphrates corridor into the Roman sphere of influence with Roman troops garrisoned as far south as Salihiye (Dura Europos), Ana (Anatha), and Kifrin. The oasis city of Palmyra, a Roman colony since the time of Hadrian, contributed to the stability on the southern flanks by acting as policeman of the Syrian Desert. More importantly, Septimius Severus created the new province of Osrhoene c. 197, confining the power of the Abgars, renowned for their political vacillations, to the city of Edessa and its immediate environs. The new network of roads allowed Nisibis and Singara to be more firmly integrated into Rome’s eastern defences, giving her valuable access to the Tigris and a choice of invasion routes. Thus, when Opelius Macrinus withdrew the army of the murdered Caracalla, whose Praetorian Prefect he was, from Mesopotamia after an indecisive battle with the Parthian king Artabanus V near Nisibis in 217, few would have predicted any major change in the balance of power. Both sides seemed set for a period of minor wars and the consolidation of their existing frontiers.
Yet, seven years later, Artabanus V was dead on the field of Hormizdagan, victim of a rebellion which began inconspicuously in c. 208. The victor, Ardashir, the scion of an Iranian royal house from Istachr, wasted no time in trying to incorporate client states of the former Parthians like Hatra and Armenia into his new dominion, in flagrant disregard of the status quo which had existed between the Roman Empire and the Parthian kingdom. Rome was not slow to send help to the threatened areas and a three-pronged expedition in 231–3 fought the Persians to a draw, with victory in Media and defeat in Mesopotamia. By 238/ 9, however, the Persians had recovered sufficiently to resume the attack on Roman Syria and Mesopotamia, capturing a number of cities, and in 240 the crown prince Shapur finally subdued the kingdom of Hatra, thus neutralizing the main threat to Persian expansion into Armenia and Upper Mesopotamia. The Roman response came four years later when the young Gordian III led an expedition which liberated some of the captured cities but suffered a major defeat near the Sassanian twin royal city of Seleucia-Ctesiphon. Gordian perished in mysterious circumstances and his successor Philip signed a pact with Shapur which was detrimental to Roman interests in Armenia. Later attempts to redress this by the Romans were the perfect pretext for Shapur (Shahanshah since 242) to direct a series of raids from 252 onwards against Syria, Commagene, and Cappadocia. The capture of Antioch, the metropolis of Syria, by the Persians would have undoubtedly sent shock waves reverberating through all the eastern parts of the Roman Empire. Against these razzias Rome made no effective reply, thus encouraging Shapur I to launch a full-scale invasion of Roman Mesopotamia via the Tigris route in 260. An attempt by Valerian (emperor 253–60) to oppose this led to his defeat near Edessa and captivity in Persia. The victorious Persians plundered Syria, Cilicia, and Cappadocia at will and were only halted by local resistance by Valerian’s officers at Pompeiopolis and the unexpected rise to prominence of Odaenathus, the prince of Palmyra, who seized the opportunity of the power vacuum created by the conflict in the north to raid deeply into Sassanian-held Mesopotamia (Assuristan). His victories kept the Persians at bay but Rome had effectively lost control of territories south of the Anti-Taurus, especially when, under Odaenathus’ successor Vaballathus (with his mother Zenobia ruling as regent), Palmyrene power extended into Egypt. The success, however, proved to be short-lived as Rome had now realized the need for stronger men at the helm. Under Aurelian (270–5), the first of a series of soldier-emperors who would restore military discipline and revive Roman fortunes in the face of foreign adversaries, Rome regained control over her Near Eastern possessions from the Palmyrenes after a decisive victory outside Antioch in 272.
The death of Shapur I, c. 272, heralded a period of political unrest in Persia as his immediate successors, Hormizd, Bahram I, and Bahram II, all had very short reigns. A struggle for power broke out after 282 between Bahram III, the descendant of a minor queen or concubine of Shapur, and Narses, the king of Armenia, the last of Shapur’s sons. The Roman emperor Carus took advantage of this and made a successful raid against Assuristan in 283, penetrating as far as Seleucia-Ctesiphon. His death on campaign compelled the Romans to withdraw and on the mysterious death of his successor Numerianus, the army elected Diocletian, a soldier from Dalmatia, as emperor. He used the years of relative peace to overhaul the defence of Rome’s Eastern Frontier, constructing a major line of communication across the Syrian Desert from Sura on the Euphrates to Damascus via Palmyra. The line (limes) was interspaced with a series of fortresses and camps for patrolling cavalry units. In 296, Narses, now secure on the throne of Persia, took to the offensive and defeated Diocletian and his junior colleague, the Caesar Galerius, near Carrhae. The fact that he seems to have been unable to exploit his victory is a testimony to the frontier reorganization carried out in the intervening years. With a fresh army Galerius surprised Narses in Armenia and scored a major victory, capturing the harem of the Shahanshah, thus forcing Narses to make major territorial concessions beyond the Tigris (the Transtigritanian regiones) to the Romans in the negotiations conducted in 297/8.
The new gains confirmed the upper reaches of the Tigris as Rome’s first line of defence and gave the cities of northern Mesopotamia like Amida, Nisibis, Singara, and Bezabde a new defensive role. They also ensured Persian hostility as no self-respecting Shahanshah would allow the matter to rest. The steady growth of the Christian community in the Eranshah introduced a new ingredient to Romano-Persian relations after the persecution of Christians came to an end in the Roman Empire under Constantine, who also actively promoted Christianity as one of the official religions of Rome. Not long before hostility resumed between the two empires in 337, Constantine put himself forward as the advocate of the Christians in Persia, adding a possible religious dimension to the impending conflict. The Diocletianic frontier reforms proved their worth in the long reign of Constantius II (337–62) as Shapur II (309–79) made repeated and fruitless attacks on Nisibis. Though some cities were lost to the Persians in 359/ 60, the valiant defenders of Amida, Singara, and Bezabde inflicted such heavy casualties on the enemy that Shapur was unable to follow up or consolidate his gains. However, three years later, the premature death of Constantius’ successor, Julian, in the course of his Persian campaign (363) led directly to the loss to the Romans on the negotiating table of three of the five Transtigritanian regiones which they had gained through the victory of Galerius, as well as of Nisibis and a number of key fortresses. The citizens of Nisibis, who had proved their loyalty to Rome on so many occasions, were allowed to be evacuated under truce to the west, leaving their city to become a major Persian stronghold on the very doorstep of the Roman Empire.
The study of the events outlined in the above section has long been bedevilled by the lack of a coherent and reliable ancient authority. The loss of the first thirteen books of the Res Gestae of Ammianus Marcellinus has left a gap in chronological narrative down to 353 which is only partially filled by the history of Herodian, the Historia Nova of Zosimus (which itself has gaps, especially on the reign of Diocletian), the highly problematic Scriptores Historiae Augustae, and the polemical Historia adversus Paganos of Orosius. Though a number of important sources on early Sassanian history exist in oriental languages (especially in Arabic, New Persian, and Armenian), they are relatively late compilations and the political and military relationship between Rome and Persia was rarely the main interest of the compilers. In the case of the Armenian sources, scholars since Whiston and Gibbon have noted that they abound in problems of genealogy and chronology, which means that they cannot be regarded as reliable or independent, or even be used as a check on the more contemporary classical sources. Nevertheless, the period is covered in outline by a number of epitomes of Roman history (especially those of Aurelius Victor, Eutropius, Festus, and the anonymous Epitome de Caesaribus) which were all compiled in the fourth century, and also by Byzantine chroniclers like Petrus Patricius, Malalas, John of Antioch, Theophanes, Syncellus, Cedrenus and Zonaras who had access to earlier material now lost to us. Moreover, contemporary documents like the works of the Church Fathers and the Latin Panegyrics make occasional references to the events in the east. And in the thirteenth book of the so-called Sibylline Oracles we have the work of an author who was well informed on Romano- Persian wars and particularly their effects on Syria from the reign of Gordian III to the domination of the province by Odaenathus of Palmyra. For the early wars of Constantius, we also possess the poems (in Syriac) of one eyewitness, Ephrem Syrus, and the panegyrics of two contemporaries. Julian and Libanius. Though Libanius himself was not a witness to the fighting, he personally knew a number of the officers who held important military commands in the east and with whom he corresponded regularly.
The dismemberment of the Ottoman Empire by European powers after the Treaty of Versailles opened Syria and Iraq to systematic archaeological surveys and selective excavations. The pioneering work of Poidebard, Mouterde, and Stein in the use of aerial photography has afforded us a better understanding of Rome’s frontier defence system, especially of the Syrian and the Arabian limes. Though the number of inscriptions from the region remains small, they yield much new information, especially on the history of the Roman army in the frontier regions. As many of them are dated, they also serve as an important correlate to our literary evidence. Those from Palmyra, in both Greek and Palmyrene, have proved particularly valuable to both our understanding and dating of certain important events in the third century, especially those related to the rise and fall of the city as a major political power between the two empires. The excavations at Dura Europos yielded a number of important documents on papyri, especially the files of the Twentieth Cohort of the Palmyrenes, and these go down to within a few years of the capture and destruction of the city in 256. The trilingual Great Inscription of Shapur on the Kaaba of Zoroaster, first discovered in 1936 near Persepolis, gives us a detailed and unique account of the three main wars of Shapur I against the Romans, albeit solely expressing the Persian point of view.
Modern scholarship on Rome’s Eastern Frontier and her relationship with Persia, her chief adversary, in the third and early fourth centuries, then, is based on the critical examination of this very wide range of literary and archaeological evidence. The fact that the relevant texts exist in more than half a dozen ancient languages imposes a considerable burden on the researcher and puts the subject out of the reach of the average undergraduate. Jean Gagé’s La Montée des Sassanides et l’heure de Palmyre (Paris, 1964) remains the only work known to us which attempts to make some of this diverse material available to the non-specialist. However, its small selection of classical sources makes any critical evaluation of Rome’s part in the struggle impossible and the epigraphical material is represented by only three Sassanian royal inscriptions and the famous Tariff of Palmyra which was inscribed in AD 137, almost a century before the rise of the Sassanians. Gagé’s collection also stops with the reign of Diocletian, while the historiographical problems which necessitate such a collection continue until the last years of Constantius II. The work of Felix, mentioned in the Foreword, is the only systematic attempt to locate the main classical and Byzantine sources on Romano-Sassanian relations but the work is purely a commentary, containing neither text nor transition.
The present collection is divided into two parts and the division does not represent a natural chronological break but a major difference in the presentation and organization of the material. Part One contains translations of all classical and Byzantine sources on Romano-Sassanian relations from c. 224–c. 350, i.e. from the coming to power of Ardashir to the end of the early conflict between Shapur II and Constantius II. It includes material on the rise of the Sassanians in order to allow the collection to be used as a corpus of Roman and Byzantine sources on the early history of the Sassanian Dynasty. The only major omissions, necessitated purely by the problem of space, are the Greek version of the Acts of the Persian Martyrs under Shapur II and Sozomen’s Historia Ecclesiastica account of the same (hist. eccl. II, 9–15). The extracts are grouped under headings in chronological sequence; under each heading, the extracts are given chronologically according to the generally accepted date of composition of the source. We are aware that such an arrangement implies a high degree of interpretation, especially when problems of dating surround particular events. It also means taking the relevant material out of its literary and historiographical context, and, in the case of the extracts from the Augustan History, running the risk of presenting probable fiction as palpable truth. However, the information we are seeking is often of a specialized and well-defined nature which lends itself to being studied in isolation. Where knowledge of the context of the extract is essential to its evaluation, we have tried to indicate this in the notes. Furthermore, it is only through juxtaposing the extracts from the Augustan History with all other known sources on the same topic that we can determine their historical value.
From 353 onwards, we have a superlative and substantial eyewitness source to the main events on the Eastern Frontier in the Res Gestae of Ammianus Marcellinus. He was one of the defenders of Amida in 359 who survived the subsequent massacre at the fall of the city to take part in the ill-fated Persian expedition of Julian in 363 (XVIII, 5–XIX, 9 and XXIII, 2–XXV, 8). In view of the different state of the sources, Part Two of our collection follows a very different format. Since an excellent modern English translation of the main parts of Ammianus’ historical work including nearly all the relevant material on the Eastern Frontier and the Persian Wars from 353 to 378 is now generally available (Ammianus Marcellinus, The Later Roman Empire, translated by W.Hamilton, and introduced and annotated by A.Wallace-Hadrill, London, 1985), the need to include lengthy extracts from it is no longer justifiable in terms of space and cost. The same applies to the other two main literary sources on the Persian Expedition of Julian, namely Oration XVIII, 212–75 of Libanius and Book III, 12–34 of the Historia Nova of Zosimus, as reliable English translations of these works, by A.F.Norman (LCL, London, and Cambridge, Mass., 1969) and Ridley (Canberra, 1982) respectively, are also readily available. (We have, however, included passages from these three authors in Part One of our collection as the ‘flashbacks’ from Ammianus and Libanius often provide valuable pin-point information on earlier events. As for Zosimus, his exclusion from Part One would deprive the reader of one of the more coherent narrative sources on third-century history and would make the reconstruction of the events immensely more difficult.) The two chapters in Part Two are each preceded by a chronological analysis of the sources including Ammianus, Libanius, and Zosimus. This is then followed by the translated sources, listed alphabetically, a format well-known to many ancient historians through its adoption by the revisers of G.F.Hill’s much-used source collection for the study of the Pentekontaetia (Sources for Greek History between the Persian and the Peloponnesian Wars, a new edition by R.Meiggs and A. Andrewes, Oxford, 1951).
Since this is a predominantly literary collection, the selection of epigraphical material has inevitably been difficult, not least because of the signal contribution given to our knowledge of the physical evolution of the Eastern Frontier by the study of inscriptions on a regional basis. The problem of space limits us to a selection of the more often cited, and therefore the more important, inscriptions, especially those which provide information on events described in the literary sources. We have included a number of recently published inscriptions like the dedication to Septimius Odaenathus of 252 published by Gawlikowski and the ‘praetensio’ inscription from Azraq published by Speidel, in recognition of their significance even though other scholars have not yet had the opportunity to comment on them. A small number of oriental sources are given in the appendices, chosen mainly according to the same criteria as the epigraphical material. Syriac sources, however, are included in the main body of the collection because they are often contemporary or near contemporary with the events they describe.