Chapter One: Physical and Human Geography. starting with pg. 24.
The region with which we are here concerned comprises the Roman provinces of Syria, Mesopotamia, Judaea (or Syria Palaestina) and Arabia. In modern terms, these represent Syria, Iraq, Lebanon, Israel and Jordan, together with neighbouring parts of Turkey, Saudi Arabia (the Hedjaz) and Egypt (Sinai). In antiquity, this broad sweep of land between the rugged mountain terrain of eastern Anatolia and the barren desert of the Arabian Peninsula was often referred to loosely as 'Syria'.
Geographically the region is zoned from west to east. A narrow strip along the Mediterranean coast offers useful agricultural land and ports, a number of which are on islands. Most rivers begin in the chain of mountains which rise steeply behind the coast and form the next zone. The mountain ranges fall into five sections, which are, proceeding from the north to the south: the Amanus Mountains, the Ansariyeh Mountains, the towering Lebanon and Anti-Lebanon, which rise to over 2500 m., the rather lower hills of Judaea and Samaria, and finally the Negev Desert and the hills along its eastern fringe. Passes cut through or between these ranges. Beyond them runs a chain of three major rivers: the Orontes, the Litani and the Jordan. The first two of these, rising within a few miles of each other west of Baalbek (Heliopolis), run respectively north and south for considerable distances before turning through gaps between the mountains and flowing into the MEditerranean at Seleucia and just north of Tyre, respectively. The ever-deepening valley of the Jordan, running south through the Sea of Galilee to flow into the Dead Sea, is extended by the dry Wadi Araba down to the Red Sea. Beyond these coastal mountain ranges the land remains high, usually over 500 m., until it eventually falls to low levels in southern Mesopotamia.
Not that the inland region is featureless. Starting north-east of Damascus, the Jebel Rawaq, rises up and runs north-eastwards to Palmyra. Beyond Palmyra, the squat range of the Jebel Rijmen, north and north-east of the city,e xtends half way to the Euphrates. Further still to the north-east is the Jebel Cembeh, extending eastwards from Tunainir and then rising steeply to become the more formidable Jebel Sinjar which reaches to wihtin 60 km of the Tigris. No mountains lie between the Jebel Rijmen and the Jebel Cembeh.
Some distance south of the Jebel Cembeh, and extending for about 150 km southwards towards Anqa on the Euphrates, is a series of wide salt marshes, which formed a natural barrier. From the Tigris to Damascus, and then southwards to the Red Sea, the typical land surface is a gravel desert, but this is interrupted by silts in the river valleys, and by the lava desert in the region south and south-east of Damascus, where the ground is covered by the black basalt of ancient volcanic eruptions, in the form either of lava flow or thickly strewn rocks.
The land on both sides of the coastal mountains, the coastal zone and the eastern slopes, is well watered and fertile - the valley of the Orontes in particular supported a series of great cities. Further inland, with the exception of the area in the north towards the Euphrates bend, and the Hauran, south of Damascus, this fertile belt soon gives way to region sof steppe and desert extending eastwards to the Zagros Mountains of Iran and south-east to the Arabian Peninsula. Most of the inland region is insufficiently watered to allow dry farming, the limit of which is marked by the 200 mm. isohyet, though in the steppe area limited agriculture is possible if rainfall is "harvested" and utilized for irrigation. There are major oases at Palmyra and Azraq, but elsewhere the desert south of the 200 mm. isohyet offers only sparse grazing for the nomad's flocks of goats and camel herds, which were watered at occasional, in places seasonal, wells, water-holes, or streams in wadis. However, the "desert line", i.e. the boundary or transition between the desert and the region regularly cultivated by village-dewelling farmers, was not always the same. Fluctuations in local security or in rainfall could move it back and forth even over short periods. In the far east of the region are the valleys of the Euphrates and Tigris, and those of their tributaries, especially the Balikh and Khabur. There the ribbon of land near the river, as well as adjacent irrigable land, was settled and farmed intensively.
Settlement within the region was at its densest in the area of great cities. Antioch at its height, with perhaps a quarter of a million people, was one of the three great cities of the Roman Empire (alongside Alexandria and Carthage). There were many other great urban centres: Laodicea, Berytus, Tyre, Sidon, Jerusalem, Apamaea, Damascus and Palmyra, all but the last on the coast or within 80 km. of it. Rural populations could be large; in the time of the Emperor Augustus, a census recorded 117,000 citizens in the city and territory of Apamaea, while Galilee was renowned for its large population. Beyond this fertile strip, good arable land and the availability of water were the crucial factors determining the location of population. In the semi-desert and desert, as noted above, these favourable conditions were found in the valleys of the Euphrates, Tigris and their major tributaries on the eastern side of our region, and on the steppe areas of the desert margins on the western side.
The population of the region was overwhelmingly Semitic: Arabs in the steppe and desert regions, including Hatra and much of Mesopotamia, Palmyra, Emesa, Ituraea, the Hauran and Arabia Petraea; Jews in not only the province of Judaea (or Syria Palaestina), but also in the adjoining parts of Syria and as major elements in the great cities throughout the region; Phoenicians along the central and northern Levantine coast; and thorughout, a sub-stratum of the older Aramaic population. There were also Greek, or rather semi-Greek, populations in many cities, especially the great Hellenistic foundations of the north - Antioch, Laodicea, Seleucia and Apamaea; a small number of Italians, some who had arrived as traders and administrators, and others among the veteran colonists who settled at Berytus, Heliopolis and Ptolemais. Other subject peoples of the Empire, most notably Gauls, Thracians, Spaniards, Egyptians and Moors, appeared as soldiers, many of whom subsequently settled, and here and there were to be found Parthians, mainly refugees and their descendants.
This heterogeneous population was reflected in the range of languges in use. Latin would have been little heard outside the army camps and the governor's administrative staff; even in the veteran colonies Latin soon disappeared. Greek was the dominant language amongst the bulk of the urban populations, used by immigrant and Hellenized native alike, though many must have been bilingual. Both urban and especially rural people also spoke various dialects of Aramaic and proto-Arabic - Hatrene, Syriac, Palmyrene, Nabataean and Safaitic, all of which were written languages, surviving on inscriptions and occasionally on documents.
: Economically, this was an important region. To a substantial population and good agricultural lands, one could add a rich transit traffic. The great cities of the Roman Mediterranean received their luxury items from the Orient (silks, spices, ivory, furs, carpets and embroiders), as well as "Syrian" exports (glass, textiles, cotton, figs, dates, wines and slaves), through the succession of ports which marked the Levantine coast from Cilicia to Alexandria. Beyond, passes through the mountain chain linked these coastal cities to the communities of the interior, and beyond again, there were routes which could be followed across the steppe and desert. Natural routes across northern Mesopotamia, along the Euphrates, across the central and southern Syrian Desert, into the interior of the Arabian Peninsula, through the Red Sea and up the GUlf of Aqaba, brought importance and commercial prosperity to a host of cities. These were also the entry points of much merchandise from elsewhere in the Empire; in particular, some, such as Seleucia, had a vital role to play in the supply of the armies of the region.
The deserts were not the sole preserve of caravan traffic. Nomads lived there. Then, as until very recently, they led a spartan existence, dependent on rare perennial springs and seasonal water courses for themselves and their animals. Consequently, their life was one of constant transhumance with the flocks of goats and herds of camels which were the basis of their primitive economy. Nomad and farmer interacted to some extent. There was some modest trading and the animals oculd be grazed on the stubble of the farmer's fields, which they simultaneously manured. The relationship between Arab nomad, and Arab semi-pastoralist and the farmer varied not only across time but from region to region. Kinship was not always a guarantee of harmony and on occasion nomads preyed on merchants or settlements on the desert's edge.
The settled parts of this great region form what old books on ancient history called "fertile crescent", with its western tip in Palestine, now Israel, and the occupied territories, and its eastern tip on the Gulf. The Roman Empire had a firm hold on the western end of this "crescent" and its central part in Northern Syria. Beyond this, towards the River Tigris, lay debatable lands, and in the far east of the zone was the sphere of Parthia and later the Sasanian Empire. The concave side of the "crescent" was on the south, roughly outlined on the map by the 200 mm. isohyet; beyond lay the desert.
Since the Roman desert limes has been little studied until recently and since some readers may be unfamiliar with the line it followed, it may be useful here briefly to describe its course. Very approximately, the western part of the limes coincided with the 200 mm. isohyet. Commencing at the head of the Gulf of Aqaba, it ran north through the modern country of Jordan, with an offshoot through southern Israel. Near Damascus in Syria it turned northeast towards the Euphrates, taking advantage where possible of the line of mountain ranges and incorporating the oasis of Palmyra. After reaching the Euphrates, it followed the river south-eastwards for some distance, and here it may be said to have reached the debatable lands. From the confluence of the Euphrates with the Khabur the limes went north and north-eastwards to cut through the "crescent", taking advantage first of a river line and then a mountain range.
Behind the limes lay densely populated regions, some of the most important parts of the Empire. Beyond its southern part there was quite different terrain - desert, with nomad peoples. After it had turned north to cut through the "crescent", there was again desert beyond it in places, but there were also areas which had carried large populations from the earliest times.
Chapter Two: Historical Survey
Roman rule over the Semitic provinces of the Middle East extended across some seven centuries. In 64/3 BC Pompey the Great entered the area and, refusing to restore the former Seleucid Hellenistic dynasty, which had declined into warring factions, organized what was left of their kingdom as the Roman province of Syria. At the other extreme, the annihilation of the field army of the Emperor Heraclius at the Battle of the Yarmuk in AD 636 ended forever Roman rule over the lands south of the Taurus Mountains.
The military requirements of the region varied greatly with the changing political and economic background. There were, however, at all times two main considerations determining the size of garrisons and their distribution: the need to secure and police the population - particularly those of the great urban centres and in the mountainous areas and desert fringes, and the need to protect from external threat the sources of wealth - the cities and their rural populations, and various important natural resources. A limiting factor to the routine implementation of a policy was the need to place major units where they could be sustained with food and supplies. Ancient agricultural surpluses were low and troops had to be located where either they would not be competing with some existing major population centre or food could be brought in. In practice the dispositions made for either of these could overlap with those required for the other.
. Most of the great cities were within 80 km of the coast, some of the largest being in the north. The concentration of so many people in a single centre such as Antioch raised the danger of disturbance amongst what was a racially mixed and, on occasion, volatile population. In the south, Jerusalem was not only a large city but also the political and religious centre of a numerous people. The Jews became increasingly alienated from Rome in the Early Principate. Sporadic insurrections were followed by bloody rebellions in the time of Nero and Hadrian. There may have been an uprising of some sort as late as the reign of Septimius Severus (193-211) and the Caesar Gallus (351-4) certainly had to put down a rebellion in Galilee. Clearly, however, the wholesale slaughter and dispersal of the Jewish population of Syria Palaestina in the first and second centuries ended the major revolts. By the late third century the two legions which had been based there since the early second century had both gone.
The External Threat: Parthia
External threats came from two directions: on the one hand, the Parthians and their Persian successors, and on the other, the Arab nomads of the Syrian Desert. When a Roman army first arrived on the Upper Euphrates in eastern Anatolia in probably 96 BC, much of the great sweep of land from Mesopotamia across Iran to Afghanistan was subject, directly or through subordinate kings, to the Parthian Arsacid dynasty. Formerly, until conquered by Alexander the Great, this region had been the heartland of the Achaemenid Empire (550-350 BC) of Cyrus, Darius and Xerxes. Alexander's successors, the Seleucid kings, had ruled over it from their twin capitals of Antioch on the Orontes and Seleucia on the Lower Tigris. However, in the generation before the arrival of Rome on the Euphrates, Iran and even the eastern capital at Seleucia, had gradually been lost to the Parthians. For the next six centuries, first the Arsacid dynasty of Parthia, then their neo-Persian Sasanian successors, were to represent the single most potent threat to Rome on her eastern frontier, the only power comparable to herself in size or power she faced on any of her frontiers.
Not that the threat was unremitting. Far from it. Although early amicable contacts between representatives of the two empires soon deteriorated, wars were in fact uncommon before the third century. The reasonable Parthian expectation that the boundary between the two empires might be the Euphrates was soon to be dashed by Pompey whose forces in the mid-60s BC crossed the river and drove deep into Armenia and the Caucasus. Indeed, they even crossed the Upper Tigris and one Pompeian general returned to Syria across the breadth of northern Mesopotamia.
A major reversal came a decade later when the Triumvir, M. Licinius Crassus, for reasons of personal ambition, provoked a war with Parthia and invated Mesopotamia. His disastrous defeat and death at the Battle of Carrhae in 53 BC opened Syria to the first Parthian invasion. Raids took place in 52, and in 51 came a major invasion. Though Cassius, the de facto governor of Syria after Crassus' death, inflicted a defeat, a Parthian army wintered in northern Syria and the province remained in turmoil. Internal dissension within the Parthian royal family, however, ended the invasion and the Parthian threat faded for a few years.
Pompey negotiated with Parthia for support in 49 BC at the outset of his civil war against Caesar. It was not till 45, however, that a Parthian force appeared in Syria and was able to raise the siege of a Caesarian army of a Pompeian army inside Apamaea. In 44 some of this force was found with Cassius, who sent them home to seek more extensive support for him in the new round of civil wars. Once again their support was too late; the decisive battle was fought at Philippi a few months later. However, in 40, soon after the victor of that battle, Mark Antony, had passed through Syria to Egypt, a major Parthian invasion of Syria tok place. Alientated by widespread Roman corruption and extortion, many cities opened their gates to the Parthian prince, Pacorus, and all but Tyre fell into his hands. The occupation was short-lived. Antony's general P. Ventidius Bassus soon drove them out in a succession of victories - the second resulting in the death of Pacorus - in 38 and 39. IT was to be two centuries before a Parthian army again appeared in Syria.
The wars however were not over. Antony's attempted revenge for Roman defeats and loss of prestige nearly ended in disaster when he led an army through Armenia into Media in 36 BC. That however was to be the last direct clash of Roman and Parthian for nearly a century.
There had been important lessons for both. By the end of the 30s each had tasted victory as well as defeat. Rome was to remain the more aggressive, but there was now an undoubted wariness of the military ability of a state which had seized much of the former Achaemenid and Seleucid empires, and inflicted signal defeats on major Roman armies.
It was now clear that though Roman expeditions could take many months to preapre, Parthia's lack of a standing professional army revealed a great weakness already evidenced by her slowness in responding to the appeals of Pompey and Cassius. However, if the feudal nature of her organization made her slow to gather her strength for aggressive warfare, the reaction time for countering a Roman invasion of her territory was rather faster. More important for Syria was that the scene of likely and actual warfare moved northwards. The mountains of Armenia not only offered Roman armies some protection against the formidable Parthian cavalry, but geographically the region became a bone of contention until Rome gained a more lasting advantage in the second century. At that point the war zone moved south to Mesopotamia. However, the Roman planners did not enjoy our hindsight. Even if Roman expeditions until the time of Trajan were in practice to be across the Cappadocian rather than the Syrian frontier, the Parthian threat to Roman territory was long perceived to be towards Syria. The Syrian Euphrates was literally and figuratively the direct point of contact between the two empires.
The Emperor Augustus threatened war with armies on both Capadocian and Syrian frontiers, but ultimately achieved his ends - the recovery of the lost eagles of Roman legions anda dominant role in Armenia - by diplomatic means. Disputes arose over Armenia, but it was not to be until the reign of Nero (54-68) that a great war broke out in that region. Even then,and only on one occasion, and in Armenia not Syria, did Roman and Parthian forces clash. Not that Syria did not seem threatened. The historian Tacitus explicitly tells us how in A D 62 the governor of Syria, C Domitius Corbulo, fortified the Euphrates' bend in the face of a possible Parthian attempt to break into his province. None of his forts has yet been identified.
The next major war - the first extended warfare between the two - came half a century later. The Parthian War of II3-I7 saw Roman armles, for the first time since Crassus, thrusting across Mesopotamia. His forces advanced down the Tigris and Euphrates. Ctesiphon, the Parthian capital, fell and new provinces were declared: Mesopotamia (northern Mesopotamia) and Assyria (Babylonia), as well as Armenia to the north. These were short-lived; rebellion and Trajan's death gave his successor Hadrian his pretext to abandon them. Trajan's reign, however, marks something of a watershed in the history of the desert frontier. The Parthian War itself was a great aggressive adventure aiming permanently to cripple, if not fragment, Parthia. Not only did Trajan aim at seizing large new territories which would have needed garrisons, but, as noted above, he completed the process of annexing allied native states west of the Euphrates and the desert. Thus Arabia Petraea was annexedi n 106 and a garrison established, including a legion at Bostra, which became the capital of thenew province.
Trajan's war was to be the first of several thrusting deep into Parthian territory. Half a century later, in the wake of initial defeat in Armenia and a Parthian invasion of northern Syria, Roman armies struck back. Ctesiphon was sacked once more and Roman direct control was again pushed beyond the Euphrates. This Parthian War (162-5) in the reign of Mlarcus Aurelius was, however, rather more modest in its territorial ambitions than had been that of Trajan. Roman garrisons were pushed further down the Euphrates and occupied Dura-Europos, while others appeared on the River Khabur, effectively turning the former Parthian vassal kingdom of Osrhoene in north-western Mesopotamia, into a Roman vassal. By 165, Rome ruled, directly or indirectly, the whole sweep of territory from the headwaters of the River Khabur to the Gulf of Aqaba.
Intervals between warfare had shortened and with the Severan period wars were to come in swift succession, foreshadowing a very different situation in the third and subsequent centuries. Septimius Severus' First Parthian War of 195-6 took Roman armies across northern Mesopotamia against Parthian allies and vassals on the Middle Tigris, and resulted in the annexation of part of Osrhoene as a province of that name. The Second Parthian War of I98-9 followed the paths of Trajan and Marcus Aurelius: Ctesiphon was captured, and new territory seized. A province of Mesopotamia was created, extending to the Middle Tigris and with two legions in garrison. Control may even have been pushed further down the Euphrates. Less than 20 years later, in 216, Septimius' son and successor Caracalla, launched another aggressive war, cut short by his own assassination. The next emperor, Macrinus, fared badly and peace was made in 218. It was to be the last war with Parthia.
The ExternaI Threat: Persia
By the close of the second century, Parthia had been in gradual decline for several generations. The extensive Arsacid family clung to royal power, but it had suffered from civil wars and too powerful vassals. The expeditions of Severus had further weakened the dynasty and, at the time of Caracalla's assault on Parthia in 216, his opponent Artabanus was already distracted by war with an internal rival. More to the point tne ruler of Persis, nominally a vassal kingdom, rebelled about this time and began extending his power over adjacent lands. In c. 224 this 'Neo-Persian' king, Ardashir, a descendant of one Sasan, defeated and killed Artabanus and proceeded to establish his control over what henceforth is traditionally called the Sasanian Persian Empire.
Conditions changed almost immediately. The new empire was much more tightly controlled, and its rulers, fired by religious zeal, laid claim to all the lands of their Achaemenid Persian predecessors. In the west, that meant lands which now formed the eastern provinces of the Roman Empire from the Aegean to the Nile. The new rulers themselves were also aggressive and able men who, in contrast to their Arsacid predecessors, whose claims to the region were rather half-hearted, rapidly and vigorously took the offensive against Rome.
Septimius Severus had claimed that his new province of Mesopotamia was to be a bulwark for Syria. Cassius Dio was to write, however, that even within his own lifetime (he died post-229), it was proving to be a cause of new war and a drain on resources. And Dio may not even have lived to see the first of the major wars of the region.
In 230 Ardashir invaded Mesopotamia and besieged Nisibis; raids were mounted against Syria. The consequent war when the Emperor Severus Alexander came east with an army in 232, is little understood. The outcome, however, after mixed success for both protagonists, seems to have been the retreat of the Persians. Ardashir was undeterred and returned to the attack, probably in 238, with the capture of Carrhae and Nisibis in Mesopotamia; probably then or sooner, his armies also captured Hatra. Increasingly preoccupied in the west by civil upheaval and barbarian attack, the Roman response was again slow and it was not till 243 that the Emperor Gordian III arrived to drive them back, subsequently losing his life in the course of his advance. With Ardashir now dead, Gordian's opponent had been his son, Shapur I, a man of enormous energy and unfortunately for Rome, great longevity - he was to rule for some 30 years. As such, his reign spanned very closely the period of Rome's greatest weakness, his actions indeed being a major contributor to it.
The murder of Severus Alexander in 235 had ushered in a period of short-lived emperors and civil wars which were to persist for half a century. Bad enough in itself, it was unfortunately only part of a calamitous cycle also involving extensive external war which was in large part responsible for the internal upheavals and for their continuace. Faced with repeated barbarian assaults along the European frontiers and their deep penetration within the Empire, emperors were unable tockle vigorously the mounting crisis in the East.
Gordian's successor Philip made peace with Shapllr in 244, but the latter returned to the offensive in 252 or soon after with a catastrophic assault. Roman fortresses and cities all along the Euphrates were captured , a Roman army was annihilated at Barbalissus on the Euphrates opposite Antioch, and Antioch itself was amongst many great cities captured and sacked in Syria and beyond. A few years later, probably in 258 or 259, the Emperor Valerian himself was defeated and captured by Shapur near Edessa. Once again the Roman lands were overrun, cities and forts sacked but not held. Order was restored over most of the region only by the rallying of some scattered Roman forces and the vigorous counter-attack of the Palmyrene prince Odenathus. Subsequently, howeve rZenobia, Odenathus' widow and regent for their son, tried to assert her independence of the embattled emperors in Europe, and rule the East - further parts of which she proceeded to overrun. When eventually the Emperor Aurelian came east in 271-2, Zenobia's 'Palmyrene Empire' was rapidly overthrown and the emperor set about the huge task both of restoring and reorganizing the frontier and reasserting Roman dominion. Fortunately, it was at this juncture, in 270 or 273, that Shapur I died; his immediate successors, were lesser men - and shorter lived.
Odenathus had reputedly invaded Babylonia and assaulted Ctesiphon following his defeat of Shapur in 259/60; two decades later the Emperor Carus was certainly to do so in 283, though dying in the course of the campaign. The subsequent peace involved, probably, the restoration of the Roman province of Mesopotamia and, in the aftermath, Rome entered on a renewed period of stability under first the Emperor Diocletian (284-305) and his associates in the Tetrarchy; then the first part of the dynasty of Constantinethe Great (324-63). The period of relative weakness in Persia ended temporarily in 293 when Narseh, a son of Shapur, came to the throne (293-302). Initially his efforts to recover Mesopotamia went smoothly; Galerius, Diocletian's junior colleague, his 'Caesar', in the East, was defeated in 297 by Narseh. The very next year, however, Galerius inflicted a crushing defeat on the Sasanians and not only recovered Mesopotamia once more, but acquired new territories beyond theTigris. It was an important victory, bringing stability to the region and ending warfare for 40 years. Diocletian took the opportunity to overhaul and reorganize the eastern defences, with a large number of new forts and the reconstruction of great strategic highways. Significantly, it seems to have been atabout this same period that the Persians too began to construct in the region their own system of fortifications against Rome. One consequence was to be the tendency for wars to be fought out in the same relatively restricted area of Mesopotamia, and deep invasions of each other's provinces became rarer.
In part, peace was lasting because of the death of Narseh in 302, the short reign of Hurmazd II (30209), and the accession of the infant Shapur II. This last, however, was to prove every bit asmuch a thorn to Rome as his great namesakeand predecessor. Shapur 1I reigned for 60 years(309-79). Coming of age, he rapidly displayed his ambition to recover Sasanian control of Armenia and, in particular, Mesopotamia. It was in the latter that most of the warfare took place and, an indication of changed conditions after the great programme of fortification and a reliance on static defences, wars became largely campaigns of sieges of the great fortress cities. The pages of the history of Ammianus Marcellinus record graphically the sieges of Amida, Bezabde, Nisibisand Singara. Only with the reign of Julian do we again find an aggressive Rome taking the initiative. Julian's expedition in 363 took him to Babylonia and a victory before the gates of Ctesiphon. His return up the Tigris, however, was a catastrophe in which the emperor himself perished. The outcome was disastrous for Rome. The Emperor Jovian concluded a most unfavourable peace by the terms of which Rome abandoned Armenia, and not only gave up theTranstigritan territory gained by Galerius but ceded Roman Mesopotamia east of the River Khabur. The real measure of Roman weakness, however, is that Nisibis, the strategic key to northern Mesopotamia, which had been defended so often, was also ceded.
During the century and a third which followed, Roman-Persian wars were rare. More tothe point for Syria and Mesopotamia, they weremore often fought out further north in Armeniaand the Caucasus. Thus, for example, the war ofValens of 370-8, though directed by him fromhis headquarters in Antioch. A few years later, c.386, even in this region peace was established bythe partition of Armenia, which removed a boneof contention. Not until 42I/2 did Rome andPersia again clash in Mesopotamia. Rome wasvictorious, attacking Nisibis in 42I and, afterinflicting a defeat the next year, making peace.A brief period of hostility in the north followedagain in 439, but was soon settled and a peacemade in 442. It was as well that it should havebeen so, for Rome was heavily distracted in thisperiod by the barbarian pressure and invasions in Europe. Even within the eastern half of the Empire, the power of German generals in Roman employ, rebellions and civil war remained a preoccupation throughout most of the fifth century, but relations with Persia were not difficult. The explanation for this relative stability on the eastern frontier seems to lie in a parallel Persian pre-occupation with both internal problems and assaults on her own frontiers in the Caucasus and in the north-east. A measure of the introversionof both states during this period can be seen in the failure of Rome to act when, in 483, Persia refused to return Nisibis, which had been ceded for 120 years by the treaty signed by Jovian in 363; conversely, the Persians let pass for almost 20 years the Roman retaliatory refusal of an agreed payment to support the defence of the Caucasian passes against their common Sarmatian foes to the north.
The early years of the sixth century saw a renewal of wartare in the East, for an account of which we are indebted to Procopius, who records not the wars themselves but, in his Buildings, the detailed account of the fortification or refortification of cities and forts. War was initiated in 502 by Persia which seized fortressesi n Armenia as well as taking Amida in Mesopotamia. The Roman counter-attack retook Amida and led to the construction of a great new fortress at Dara, confronting Nisibis. A seven-years peace was made in 506 which lasted in fact until the last year (527) of the next reign. Ironically, the new war was in large part the outcome of the refusal of Justin to adopt the heir-apparent of thePersian king, Kavad; in anger, the latter initiated the new war (in the north again) but it was to be the spurned son, Khusrau I, who was to be the main protagonist over the course of a long reign(531-79).
In the war which began in 527, Justinian's generals had mixed fortune. In the north-east, victories were won by Sittas in 530, while in the Syrian region, Belisarius, who had been engaged on fort building, first won a victory at Dara in 530, then was heavily defeated the next year at Callinicum, at the confluence of the River Balikh and the Euphrates. In the event, however, it suited both empires to conclude, in 532, a Treaty of Ternal Peace: it lasted eight years.
`Khusrau's assaults on the Roman defences began in 540 and continued through to a five-year truce in 545. He made significant advances in this period, not just in the Caucasus, where he seized territory (and which was not covered by the truce), but in Mesopotamia and along the Euphrates, where his armies sacked fortress-cities or allowed themselves to be bought off. Once again, Antioch was sacked. In 551, the truce was renewed for the Mesopotamian area, though again the two empires continued to fight in the Caucasus; indeed, fighting dragged on there until 557 and then in 561, a comprehensive 50-years peace was agreed. By the terms of this latter, the existence of the great fortress city of Dara was accepted by the Persians, but no new forts were to be built by the Romans near the Persian frontier.
A new round of fighting broke out a decade later in the time of he Emperor Justin II. It went badly for Rome: they failed to seize Nisibis in 572 but the Persian counter-attack took Dara and then went on to ravage parts of Syria - including the sack of Apamaea - forcing Justin to make peace. Once again the peace only covered theSyria-Mesopotamia region, and war continued vigorously in Armenia. Khusrau's death in 579 failed to end the fighting which again flared up in Mesopotamia.
Peace was not in fact finally restored until 591, by which time both sides had been debilitated by two decades of warfare. Even then, its achievement was due to a quite unforeseen piece of good fortune for the Romans. Hurmazd IV died in 590 and a consequent civil war not only distracted Persia from further thoughts of warfare but actually worked very much to Roman advantage. One protagonist, Khusrau II obtained the help of Roman troops to regain his throne, granting in return, by a treaty of 591, territory which included Dara. While the Emperor Maurice lived, Khusrau was content to remain at peace; Maurice's overthrow by Phocas in 602, however, provoked a Persian invasion of Mesopotamia. Their victory in battle was followed swiftly by the fall of Edessa and Dara, and, in 606, the capture of Amida and Resaina led to raids into Syria. Phocas was overthrown in 610 but his successor, Heraclius, was to face on his eastern frontier one of the greatest threats of any emperor for centuries.
Khusrau II was not content, as many of his predecessors had been, with simple expeditions into Syria for booty. In rapid succession after 610 his armies struck through the Roman defences; in the north, they reached Chalcedon opposite Constantinople itself; in the south, Syria was overrun, and armies passed into Egypt, which they occupied in 619. The long-standing Persian claim to the lands of the eastern Roman Empire seemed to have been made good at last. Heraclius' counter-attack was equally dramatic. Beginning from a base in north-west Armenia, he graduallyt urned the tide through a series of victories, ultimately forcing Khusrau to recall his troops from Chalcedon. The climax came in 627/8 when Heraclius led an army down into Mesopotamia, defeated a Persian army at Niniveh on the Tigris, then marched on to the capture and sack of Khusrau's palace at Dastagird in Iran, over 300km (almost 200 miles) to the south-east.
The disaster soon led to the death of Khusrauin 628 and a period of internal strife and a whole succession of short-lived monarchs. In 632 when Yazdgird II became King of Kings, Heraclius wasalready re-established in his eastern possessions, returned by treaty after Khusrau's death.
This final great series of campaigns in which the frontier defences of each side were swept aside as bold thrusts were made into the empire of the other, were in fact to prove just wasted energy. Both empires, debilitated by the effects of this and earlier wars, civil strife and wars on other frontiers, were too weak to resist the Arab forces of Islam. In 636, at the Battle of the Yarmuk in north-west Jordan, an Arab army annihilated the main Roman army in the region and went on to overrun all of Syria; in the same year, at Qadisiyya, the Persian army was soundly defeated and in 642, after a period of resistance, the army of Yazdgird was destroyed at the Battle of Nihavand in Iran. The outcome of centuries of war was, ironically, to be the destruction of Persia and the uniting of the entire region of the Persian Empire and the former Roman eastern provinces up to the Taurus Mountains under the rule of a new Moslem Arab empirel
Th e E x t e r n al Threat of The Nomads
It will be clear from the above that only on rare occasions were sectors of the desert frontier other than those of Mesopotamia and northern Syria threatened by Parthia or Persia. Nevertheless, the semi-desert and desert from the Euphrates to the Red Sea and the Negev are studded with Roman forts. Here, however, the perceived threat could not have been the powerful army of Parthia or Persia; it has been traditional to explain these forts in terms of the threat posed by the desert's nomadic tribes.
Arabs could be found in the entire region from Mesopotamia to the Sinai Desert and Arabian peninsula. Some had settIed in great clt1es such as Hatra, Palmyra and Petra, but most retained their traditional way of life as nomads - Scenitae,'Tent-dwellers'. For such tribes in a difficult environment, a crucial factor in their simple and precarious economy was the availability of water, whlch led to thelr regular transhumance between winter and summer pasturage with their flocksof goats and herds of camels.
The presence of these nomads in the desert regions from an early stage is evident not only from the widespread physical traces of their simple structures at camp sites and from 'kites' (probably animal traps), but from the thousands of graffiti left scratched on rocks by the southern, 'Safaitic', tribes. Most of the literary evidence for them is, however, late in date.
In the first and second centuries there is a handful of epigraphic references mainly from the region of the Hauran to individuals described as'General' (strategos) or 'Tribal Chief (phylarchos) of the Nomads'. This is a period, however, when much of the land along the desert fringe was under the control, not of Roman troops, but those of various allied rulers. Thus, relations with the tribes and the task, if necessary, of policing their movements, fell to states whose populations were themselves often Arab. The removal during the first century of most of these native rulers, brought Rome directly into contact with some of the tribes. These direct responsibilities increased in the second century with the annexation of the Nabataean kingdom in 106. There was a brief confrontation with the Arabs east of theEuphrates at the time of Trajan's Parthian War and, half a century later, Rome extended her control into north-western Mesopotamia. Significantly, it is then, in the middle of the second century, that the first clear evidence emerges for a Roman garrison at Palmyra, a city which had hitherto provided its own troops to police the desert caravan routes. The corollary to this is that there is virtually no clear evidence for Roman military installations in the desert regions before the end of the second century. There are few such traces anywhere in the region in this period, but in the desert areas where structures are well preserved, their near absence may be regarded as significant and not merely the consequence of later building or agricultural activity.
There is a little evidence for the possible trouble the nomads could cause. Inscriptions from Palmyra honouring various leaders allude to trouble with the nomads: one of 132 speaks of the deliverance of a recently arrived caravan from Vologesias 'from the grave danger that surrounded it'; another of 199 honours a man for the continuous expeditions he has raised against the nomads'; and a third, of about the same period, shows us a strateos who received imperial approval for his work of pacification in the desert. A Nabataean inscription from the Sinai with the date 190/1 speaks of that as being the year 'during which the Arabs [?] ravaged the land' . But these were almost certainly modest affairs, the nomads posing no threat to major settlements, much less any of the cities of the region.
In the first and second centuries, in the absence of forts there is little information about the Roman forces only at Hegra, with some graffiti scratched by Roman auxiliary soldiers on a cliff face, and an inscription dedicated by a legionary of the III Cyrenaica, do we get some hint of where troops were. Perhaps the Roman military presence was like that of the nomads- seasonal and in tents. However, physical evidence for Roman military presence becomes more abundant towards the end of the second century, as at Qasrel-Hallabat and around the Azraq Oasis.
There seems however to have been a change taking place in tribal nomadic society in this penod which may have had serious consequences for Rome. This is the process of 'bedouinization'. It is suggested that in the early Principate there took place in the region of north Arabia a breakdown of such modest urbanism as had developed. Instead of a nomadic society influenced and controlled by a town-based aristocracy, there appeared one dominated by those already adapted to desert life. Typical bedouin society emerged with the characteristic blood feuds and raids. The case is difficult to prove. It is a fact, however, that the desert tribes begin to appear in the records from the Severan periodas a troublesome element on the frontiers, looming ever larger over the next four centuries and playing a growing role in the developing contest between Rome and Persia.
The danger posed by nomads should not beover estimated. Undoubtedly hostile if relatively small nomadic tribes could cause extensive disruption and tie down a disproportionate number of soldiers. The evidence that they did so and are xplanation for many of the forts which first appear along the desert fringe of Syria and Arabiain the third and fourth centuries, is at best thin. An interesting alternative explanation which draws on the evidence for upheaval in the Arab population of the provinces in the aftermath of the collapse of Palmyrene power in the late third century, envisages many of the forts as built to guard communications against uprooted dissident provincials operating in the difficult fringes of the province itself .
Nevertheless, nomads seem to have been more significant in Roman military thinking from the third century. There is evidence of a changed relationship; it is in this period that we begin to find the literary sources preserving the names of nomad chiefs and the names of tribal confederations become common. Thus there was Jadhima, king of the Tanukh, who fought for Rome against the Palmyrenes. It would seem that this confederation had once been localized in the vicinity of the north-west shore of the Persian Gulf, but had subsequently removed to the Roman frontier; more precisely, Jadhima is named on an inscrlptlon from Umm el-Jemal. We can hardly doubt that the downfall of Palmyra and its subsequent inability to police the desert (we hear of no more caravans through Palmyra after that of 269) gave far greater power to nomad chiefs especially one such as Jadhima who had assisted the Romans. Not that we need believe Jadhima motivated by loyalty to Rome. Rather, hostility to Palmyra seems the key.
The appearance of larger tribal groupings is notable and helps explain the growing potency of Arab chiefs in the subsequent centuries. Bedouinization need not have led to such a development. Rather, we should perhaps see it as a response to the very success of Rome. It is surely no coincidence that all round her frontiers tribes were coalescing in this period to form powerful confederations: the Maeatae who appear in northern Britain in the Severan period, the Alammani on the Rhine (and later the Franks), and now in the East, the Tanukh, responding to Roman and Palmyrene power in the same way. Indeed, it seems that the very name 'Saracen' is derived from a word meaning 'confederation'. More was to come. Within a generation, the Tanukh itself was absorbed into the new powerful Lakhmid confederation ruled over by Imru'lqais, 'king of all the Arabs', and whose power stretched from the Arabian peninsula to the Persian Gulf to the Hauran. Imru'lqais is said to have offered the service of his troops to both Rome and Persia, but it may be indicative of a closer relationship with Rome that in 328 he was buried at Nemara in the Hauran, near a former Roman military post.
The wide power of the Lakhmid kingdom seems not to have survived Imru'lqais. The confederation itself survived, based henceforth on the Sasanian frontier at el-Hira and closely allied to Persia. Indeed, for the next three centuries the desert tribes were to be largely divided between the pro-Persian Lakhmids and the pro-Roman Ghassanids who were soon to emerge on the Roman frontier. It would be misleading to present this development as simply a return to the Early Empire system of client-rulers being left in charge of difficult areas or peoples. In the Early Empire Rome was acting from a position of strength, choosing to administe rsome regions in thls manner; in the Late Empire it is clear that these Arab phylarchs were powerful and independent. Many were keen to obtain recognition in their role by Rome or Persia but they were plainly far less reliable than were the one-time rulers of Commagene or Arabia Petraea.
In the pages of Ammianus Marcellinus there is a description of the Saracens as fighters. They appear in the Emperor Julian's campaign as raiders and guerrilla fighters, well-adapted to desert conditions; in battle with the Goths it is their ferocity and barbaric appearance which arrests the attention of even their opponents.
What the appearance of such allied tribes or confederations might mean for the Roman defences begins to become clear both from literary references as to where these nomads were operating and from the archaeological evidence. Some of the more distant frontier forts such as Qasr el-Azraq in the desert itself or on its fringes began to be given up from the later fourth century, security being vested instead in the hands of individual tribal chiefs who entered into formal alliances with Rome and probably undertook the protection of travellers previously secured by the forts.
Throughout this period there are references to Saracen raids: on the hermits on Mount Sinai in c.373; another attack on those of Palestine in the early fifth century; widespread raids in Palestine, Phoenicia and Syria in 410; an attack on northestern Syria in the mid fifth century; in 473 after a period of raiding, the Emperor Leo was asked to recognize a tribal chief in the Hedjaz, Imru'lqais (= Amorcesos), as phylarch; and at the close of the century, St Sobas asked the Emperor Anastasius for a fort and garrison to protect his new monastery in Palestine, this coming at about the same time as the raids o f41I-2 which struck in northern Syria as deep as Emesa. In other respects, the fifth century was, however, apparently one without any great upheavals, perhaps because of the power and influence of a new confederation, the Salih, based in central Syria.
With the sixth century there was a resurgence amongst the Arab tribes. The period saw various major developments, above all, the appearance of the Ghassanid confederation. This, according to Procopius, was the outcome of a policy decision by the Emperor Justinian to transform one of his Arab Phylarchs, al-Harith (= Aretas), son of Jabalah, into a paramount chief with the title of patricius, probably interpreted by his followers as king. In doing so, he was evidently concerned to create on the Roman side an organized counterpoise to the powerful pro-Persian Lakhmids at Hira near the Lower Euphrates, whose raids into Roman territory were proving disruptive. Al-Harith first appeared alongside the Roman forces in 53 I1at the Battle of Callinicum but was prominent thereafter throughout the c.40 years of his reign. Ghassanid troops not only assisted as allies in Roman armies, but also conducted a war of their own against the Lakhmids c.544. Al-Harith appeared too as a more traditional king, responsible for building and the patronage of art. TheGhassanid kingship did not long survive his death: the Emperor Maurice early in his reign, ended the patriciate, retaining the Ghassanid successors as phylarchs only. The period of some half a century is significant both as reflecting the important role being played by Arab tribes on both the Roman and Persian side, the dominance nevertheless of the emperor who could apparently make and unmake a kingship, and the extent to which the defences of the eastern frontier in desert and steppe were placed in the hands of Arab allies.
Both in the time of the patriciate and later under the rule of the fragmented Ghassanid family and other Arab phylarchs, we find exte-sive tracts of eastern Syria under their authority. Not just the desert and semi-desert, but settled, urbanized areas from Resafa through Damascus and Bostra to the vicinity of Jericho. In short, many of the forts of the desert frontier, previously garrisoned by Roman troops, were now in regions under the authority of Arab phylarchs. The building inscription of 529 fromQasr el-Hallabat is the latest piece of certain evidence of direct Roman military involvement in Arabia. The peasant militia into which the limitanei had sunk, had long since ceased to have any serious military function. Imperial forces now only garrisoned the majo rtowns to the west and along the Euphrates, towns whose populations sheltered behind massive and imposing walls.
The great tragedy of Heraclius' remarkable recovery of his eastern provinces from the Persians after a titanic struggle, was that they were now weakened and disorganized by years of war and recent Persian occupation. Further, they were divided from the imperial court by religiou sdifferences. When the first Muslim assault on southern Palestine came in 629 - the only one directed by Muhammad before his death -it would have been seen as of no great significance; another Arabian tribe thrusting out of the desert as the tribal constituents of the Tanukh, Lakhmids, Kindites and Ghassanids, and many others had done before, and in due course to be assimilated as foederati, their chief recognized as phy-archus. Besides, this was the moment at which Heraclius, having freed Syria the preceding year from more than 14 years of Persian rule, was triumphantly replacing in Jerusalem the fragment of the True Cross. Muhammad's death and the internal struggle which took place in Arabia, resulted in the dramatic outburst of Arab armies in 633 which led to the overthrow of Sasanian Persia and to a series of Roman defeats culminating in the Battle of the Yarmuk in 636 and the loss of Syria to the Roman Empire.
From the earliest days of Rome's recorded history, her forces had evolved to meet changed circumstances and different opponents. In the Eastthey had to adapt to climate, geography and the military situation. The military needs of the region naturally varied over several centuries. The elimination of allied rulers and the extenion of Roman territory brought additional military rponslbilities. New conditions were created by political and social developments amongst the peoples beyond the frontiers outlined above and changes within the Roman Empire itself. As a survey of the evidence shows, changes appeared in the character of the Roman forces and in the tactics and strategy employed. Throughout the Roman period, the province of Syria had the principal military force in the entire East. Consequently, its governors exercised a general responsibility over not just the province of Syria, but the adjacent provinces too, from the Black Sea to the Red, and even, on occasion,to the Nile. Even when additional major military provinces were created in neighbouring Cappadocia, Judaea, Arabia and Mesopotamia, Syriar emained the largest and most important. Because of the military interdependence of all the provinces in the region, it is more apt to look at the forces not just in the provinces of the central and southern areas of the eastern frontier with which we are concerned, but of the Asiatic East as a whole. Much of the East was technically 'un-armed', though all governors had some troops at their disposal.
In the Late Republic, the governors of Syria were generally allowed only two legions of citizen soldiers (approximately IO,OOO men), although the civil wars had often seen many more there. With the establishment of the Principate the number increased. For the first century of the Principate, with the possible exception of a legionary province of Galatia under Augustus (c. 25 BC -AD 6), the entire Asiatic East from Sinai to Hellespont had only four legions, all of them in the single province of Syria. Three imperial provinces - Cappadocia, Syria and Judaea -emerge in the Flavian period (69-96), a fourth under Trajan with the annexation of Arabia Petraea, while with Septimius Severus, Syria was divided into Syria Coele and Syria Phoenice, and a new legionary province of Mesopotamia was created. Finally, in the Diocletianic period legions are strung out through nine provinces from the Black Sea to the Red. The legions are of course only part of the story .Unfortunately, we cannot produce a picture of the auxiliary forces (largely recruited amongst non-citizen provincials) with anything like the same confidence. Nevertheless, from Tacitus' observation (Annals IV.s referring to AD 23) that overall within the Empire auxiliary forces were broadly equal in strength to the legions, we may tentatively infer some 20,000 under Augustus and the early Julio-Claudian emperors. By the time of Nero our information has improved somewhat: the army mustered by Vespasian at Ptolemais in 67 for the Jewish War is said to have included over 22,000 auxiliaries to which would have to be added the units retained by Mucianus in Syria, and the units in Cappadocia and in the so-called 'Unarmed Provinces' of Asia Minor. However, it is for the mid second century that our best estimates are available. Including the 'Unarmed Provinces', there would have been in total some 3 5,000 auxiliaries; adding on the legions gives 75-80,000. This latter figure may hav- risen to perhaps 90,000 by the death of Severus.
The third element is that of the armies of the allied kings and princes in the region. These had their own role to play in providing internal security, but could be called upon in time of major warfare. The evidence for these armies is even more fragmentary than for the auxiliaries. Occasional references give us some idea of the order of magnitude, but it is again from the passage of Josephus just cited that we get our most comprehensive insight: Vespasian's army at Ptolemais was augmented by some 15,000 troops from four allied kings. The forces of allied kings were not, of course, a constant. The annexation of allied states eliminated the royal armies which then often appeared amongst the local auxiliary forces or were exchanged for existing units elsewhere. Thus, the annexation of the Nabataean kingdom led to the appearance in the Roman army lists of six Cohortes Ulpiae Petraeorum, some 4500 men. By the early second century, there were no longer any allied states west of the Euphrates to contribute to Roman campaigns.
The evidence for the tactical distribution of legions and auxilia within any province of the Asiatic East is patchy even when the evidence is at its best. For theJulio-Claudian period we have precise locations for legions on only two occasions (Cyrrhus and Raphanaea; Zeugma may beinferred). From a passage in Tacitus (HistoriesII.80), we may infer that some at least of the legions of the East in 69 were based amongst o rclose to the urban populations of the province. Little can be said about the location of auxiliary units except in Judaea, where cities such as Caesarea, Ascalon and Jerusalem had garrisons,as well as the border fortress palaces at Masada and Machaerus.
After 70 th s information improves, especially all that showing legions now firmly located on the Euphrates itself (Melitene, Samosata and Zeugma) and auxiliary units likewise pushed out onto the Euphrates and into the desert further south. Vexillations ('detachments') of legions appear more frequently, two at least at apparently temporary outposts in distant locations: Baku on the Caspian Sea under Domitian, and another at Hegra in the Hedjaz in, perhaps, the mid second century.
No new province was created under Marcus Aurelius but the army was thrust further eastwards again. Troops appear at Dura-Europos and a reasonable inference from the report in Dio (LXXV.I.2) of Roman troops being attacked in1I93 by the Osrhoeni and Adiabeni - Nisibis is explicitly mentioned - is that units were in central North Mesopotamia. With Severus one must suppose that auxiliary units were firmly established east of the Euphrates but only one - onthe Lower River Khabur - can be located. LegioI Parthica is now known to have been at Singara in his reign; the other legion assigned to the province was probably at Nisibis. Legionary detachments again appear operating far from the parent unit. Dura, for example, has them from three different legions. A few years later, under Severus Alexander and Gordian III, an auxiliary cohort is attested inside Hatra far to the east.
With the upheavals in the East in the mid third century, our evidence becomes very scarce and it is not until the end of the century that we can again see something of what is going on. Then the Notitia Dignitatum gives a list of units which nominally reflects the situation c. 400 but is commonly believed to have changed little since the reforms of Diocletian and Constantine. Under these emperors, the entire structure of the Roman army altered. Diocletian is conventionally -though, perhaps, erroneously - credited with massively increasing the size of the Roman army after the near collapse of the third century. The restored units and new regiments were, however, distributed along the frontiers again, rather as they had been in former times - albeit now rather more numerous. It is to Constantine that historians traditionally attribute the change which resulted in a major mobile field army developed out of the nucleus of one which had first begun to take snape in the tlme of Seplmlus Severus. To do so, however, was to some extent a matter of withdrawing some units from the frontier forces. Although initially held centrally by the emperor, this field army was later divided to provide a few regional field armies, one of which was assigned to the East. Thus, from the late fourth century through to the time of Justinian, the arrangement in the East consisted of this field army, the comitatus, held as a strategic reserve, below which came the limitanei who actually garrisoned the forts and frontier cities, then the federate tribes.
There was also a reversal of status. Legions - or rather their much smaller Late Empire successors) - were no longer the elite troops, but were now largely part of the static, relatively low-grade frontier forces, the limitanei who garrisoned most of the sites with which we are concerned here. Ancient references make it clear that increasingly the quality of these was often poor, their morale low, and, in times of monetary shortage, it was not uncommon for their payand equipment to have been neglected; they tended too to become more farmers than soldiers and less useful even as garrison troops. The units became smaller as may be seen not just from the documentary evidence, but from the size of the forts entire units now garrisoned. From time to time too, elements of this frontier force were drawn off to join the field army; in short, the trend over the three centuries to Heraclius was for the first line of defence to decline in numbers and quality and for the real defence to depend ever more on the field army. Both the comitatus and the limitanei declined in numbers. Jones has calculated that at the time of the compilation of the Notitia Dignitatum in c. 400, on paper at least, the former in the eastern half of the Empire numbered some 1o4,000; the latter in the same region, 248,000. We have no way of estimating the decline in numbers of the limitanei, but it comes as something of a shock to be told tha twhen Justinian reinforced the comitatus in the East, he brought its strength up to 25,000!
These changes in the make up of the army reflect an altered strategy and new tactics. No longer was it possible, as in the Early Principate,to concentrate the bulk of the garrison of the reglon behind the trontler and leave much ot the everyday policing to the armies of allied rulers. Rome was now responsible for the protection of a frontier often under threat and for providing a field army in time of major war. The character of the army also changed. Cavalry was more prominent, the field army as a whole being more mobile. Rome had always been willing to adopt and adapt the weapons and tactics of her opponents. Thus the huge numbers of auxiliary troops included not only infantry but the cavalry in which the Roman armies were deficient, and the archers and the dromedarii one increasingly finds in the East from an early date. Significantly in the great wars in the East, it was Rome which adopted major features of the armies of her opponents, not vice versa. Only the technique of siege war seems to have been taken up by any of Rome's enemies. Where the Parthians had been notably deficient, the Sasanians became adept. Hence the very different character of Roman-Sasanian campaigns, settling down in the third century into a series of sieges, usually of Mesopotamian fortresses, and the increasing emphasis placed by both sides on fortifications and heavily ,garrisoned strong points.
Barbarian troops become more prominent not just as foederati but in the field army and limitanei. Thus, after the defeat of Valens by the Goths in 375, it was felt necessary as a precaution to carry out a surprise massacre of all the Gothic troops in the East before they could think to rebel. In the aftermath, as Theodosius attempted to fill the gap created by the annihilation of Valen's army, many regiments were drawn westwards and new regiments introduced to the East. Since these latter, unusually, have no ethnic title, it has been proposed that they were pure barbarian units, the name being omitted to disguise their numbers. The Notitia Dignitatum also refers to several units of Arabs, some of whom were probably recruited from amongst the allied nomads. The practice continued, and a century and half later, we hear of five regiments of Vandals brought by Belisarius from Africa being sent to the eastern frontier.
In the final battles for Syria against the forces of Islam, the Byzantine armies seem modest. Even for the last battle, at the River Yarmuk the field army is said to have been only 50,000.By that time of course, the troops of the limitanei were no longer a meaningful force in any area and many of their forts will have been either abandoned or become the homes of the peasantry into which the former frontier army had disintegrated.