Battle of Argentorate

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Battle of Strasbourg
Part of the Roman-Alamanni conflict
Coin showing (obverse) head of Julian (emperor 361-3) with diadem and (reverse) soldier bearing standard holding kneeling captive by the hair and legend VIRTVS EXERCITVS ROMANORVM ("Courage of the Roman army"). Gold solidus. Sirmium mint
Date 357 Location Strasbourg Result Roman victory
Belligerents
Roman Empire	Alamanni
Commanders
Julian (deputy emperor) Severus (magister equitum)	Chnodomar (high king) Serapio (2nd-in-command)
Strength
13,000[1] (inc. est. 3,000 cavalry)[2]	ca. 35,000[3]
Casualties and losses
243 dead[4]	6,000 dead in the field.[5] Unknown but large number drowned crossing river Rhine

The Battle of Strasbourg, also known as the Battle of Argentorate, was fought in 357 between the forces of the Roman Empire under the Caesar (deputy emperor) Julian and the Alamanni tribal confederation led by joint paramount king Chnodomar.

Despite being outnumbered by 3 to 1, Julian's army won a complete victory after a hard-fought struggle. The Romans drove the Alamanni beyond the river Rhine with heavy losses, and with negligible casualties of their own. Julian's force, the imperial escort army of Gaul, was small but high-quality. The battle was won by the skill of the Roman infantry, with the cavalry performing poorly.

The battle was the climax of Julian's campaigns in 355-7 to evict barbarian marauders from Gaul and to restore the Roman defensive line of forts along the river Rhine, which had been largely destroyed during the Roman civil war of 350-3. In the years following his victory at Strasbourg, Julian was able to repair and garrison the Rhine forts and impose tributary status on the Germanic tribes beyond the border.

[edit] Sources

By far the most important and detailed source for the battle, and Julian's Gallic campaign (355-60) generally, is the Res Gestae (Histories) of Ammianus Marcellinus, a contemporary historian. Ammianus was a Greek career soldier who joined the army before 350 and served until at least 363.^[6] Enlisted as a protector (cadet senior officer), he served as a staff officer under magister equitum Ursicinus and then under Julian himself in the latter's Persian campaign. He had experience of the Gallic front as he was involved in the suppression of the revolt of Silvanus, the magister equitum in Gaul (355).^[7] His personal experience in the high command of the military of the time makes him a reliable and valuable source. However, he is revealed as a great admirer of Julian by his narrative, which occasionally descends to the level of eulogy. This probably makes him over-generous in his assessment of Julian's performance.

The late 5th century Byzantine chronicler Zosimus's Nova Historia deals with the battle, and Julian's Gallic campaign in a summary fashion and adds little to Ammianus' account. But Zosimus is useful because his account of the revolt of Magnentius (350-3) survives, unlike Ammianus', which is contained in the 13 lost books of his history.

The contemporary rhetorician Libanius delivered Julian's funeral oration (363). This contains some details which are missing in Ammianus, which he presumably learnt from members of Julian's entourage. But because his is a eulogy, not a historical narrative, the reliability of his account of Julian's campaign is doubtful, and Ammianus' version is to be preferred where there is a contradiction.

[edit] Background

After the death of Constantine I the Great in 337, the empire was divided among his three sons, the Augusti (joint emperors) Constantine II and Constans in the West and Constantius II (ruled 337-61) in the East. Each emperor was assigned a comitatus (imperial escort army, also known as a "mobile field army"). Each comitatus was ca. 30,000 strong. The 3 comitatus contained the best troops and generally accompanied the emperors on campaign. At this time, each comitatus was commanded (under the emperor) by a magister peditum ("master of infantry") and a magister equitum ("master of cavalry").^[8] In practice, these officers commanded both types of troops, with the magister peditum as the senior of the two. Sometimes only one of the two was appointed e.g. for the Gaul comitatus, which after 350 was usually commanded by just a magister equitum.^[9] The comitatus at this time contained about a quarter of the total Roman army' effectives, the rest being deployed on the empire's frontiers, denoted limitanei ("border troops"). (See Late Roman army)

In 340, Constantine II was murdered by soldiers loyal to Constans, who took sole control of the West. But although his comitatus was probably disbanded, a mobile field force appears to have been deployed in Illyricum by Constantius. ^[10] In January 350, Constans was in his turn overthrown and killed by the usurper Magnentius, a laetus from Gaul who was the comes (commander) of the elite Herculiani and Ioviani legions, which were brigaded together to form Constans' imperial guard.^[11] At this point, the three comitatus were deployed as follows:^[12] in Gaul, under Magnentius; in Illyricum under magister peditum Vetranio; and in the East under Constantius, who had been fighting a war against the Persians under Shah Shapur II.^[13]

To suppress Magnentius' rebellion, Constantius interrupted his war against the Persians in the East and led the Eastern comitatus to Illyria where he won over Vetranio and assumed command of the Illyricum comitatus, bringing his combined strike force to ca. 60,000.^[14] Magnentius gathered an army consisting of the Gaul comitatus and probably some Frankish and Saxon foederati (allies) and marched into Illyricum to attack Constantius.^[15]

The main adversaries of the Romans along the Rhine frontier were the Franks of NW Germania Libera ("Free Germany", i.e. Germany outside the empire) and the Alamanni of SW Germania. These were not tribes, but confederations of tribes which had evolved in the 3rd century, bringing together in military alliance the myriad small and fragmented German tribes that faced the Romans in the 1st and 2nd centuries. Although often riven by internal feuding, the confederations' ability to mobilise very large forces (especially under strong leaders such as Chnodomar) probably made them more dangerous to the Romans than their predecessors.^[16] Both these groups now seized on the opportunity presented by the absence of the comitatus in the civil war to overrun much of eastern Gaul and Raetia.^[17] Libanius claims that they were incited to do so by letters from Constantius, in order to create a diversion in Magnentius' rear.^[18]

Meanwhile, most of the Gaul comitatus and perhaps half the Illyricum force were wiped out in the civil war. At the Battle of Mursa in Pannonia (351), one of the bloodiest in Roman history, Magnentius lost an estimated 24,000 men (perhaps two-thirds of his army). Constantius' army, although victorious, suffered even greater casualties (ca. 30,000).^[19]. A final encounter at the Battle of Mons Seleucus in the Alps saw further casualties. Such massive losses of first-grade troops could not quickly or easily be replaced. Manpower was further stretched by the creation of more comitatus in a reorganisation after Magnentius' defeat. In addition to his own, now based in Milan, Constantius seems to have reconstituted a comitatus in the East under a magister equitum and a substantial force in Illyricum.^[20] He thus had few troops to spare for Gaul.

Constantius succeeded in driving the Alamanni out of Raetia (354).^[21] But the following year (355), the brief usurpation of Silvanus, the magister equitum in Gaul, convinced a shaken Constantius that he needed a member of his own Flavii (Constantinian) clan to take charge in the West. He thus appointed his cousin Julian as Caesar (deputy emperor) for the West and gave him the command of forces in Gaul, including a much-reduced comitatus.^[22]. The appointment was widely seen as unsuitable as Julian, who was just 23 years old, had no military experience and had until that moment spent his time studying philosophy at Athens.^[23] But Constantius had little choice: Julian was his sole surviving male relative as a result of the emperor's own paranoid purges of his family members. In the event, Julian surprised everyone by proving a highly effective military leader.

The task confronting Julian as he took up his post was daunting. The civil war had left Gaul in a chaotic state.^[24] The defensive line of the Rhine had largely collapsed. According to Ammianus, the Franks had taken Colonia Agrippina (Cologne) by storm and razed it to the ground. Moguntiacum (Mainz), Borbetomagus (Worms), Nemetae Vangionum (Speyer), Tabernae (Saverne), Saliso (Brumat) and Argentorate (Strasbourg) were all in German hands. Their fortifications had been destroyed and the Germans had established permanent camps just outside them, which they used as bases for raiding the interior of Gaul. Only three strongpoints on the Rhine remained in Roman hands: a single tower near Cologne and two forts, at Rigodunum (Remagen) and Confluentes (Koblenz).^[25] Large barbarian bands were roaming and pillaging eastern Gaul at will, reaching as far as the river Seine.^[26] So many and numerous were the marauding enemy bands that Silvanus was considered a brave man for having led 8,000 men along a wooded highway in the heart of Gaul because of the risk of ambush.^[27] At the same time, the forces at Julian's disposal were very limited. The comitatus of Gaul was seriously understrength due to the losses incurred during Magnentius' rebellion. Julian's army at Strasbourg numbered 13,000, only a third of the army Magnentius fought with at Mursa.^[28] Further, the limitanei (border forces) along the Rhine must have been decimated by the fall of most of their forts to the Germans. The Caesar 's failure was seen as so certain, that cynics whispered that Julian had been given an impossible mission to rid Constantius of a potential rival for the throne.^[29]

[edit] Prelude

4th century Roman foot soldier. Note the differences with 2nd century attire: trousers instead of bare legs; boots instead of sandals. The tunic has long sleeves, unlike the short-sleeved tunic of the Principate. Note the nose-guard on the Intercisa-type helmet (two sections riveted together, rather than the single-bowl Imperial Gallic type of the 1st/2nd . This soldier is armed with a single heavy thrusting-spear.

Julian spent the winter of 355/6 with his army at Vienna (Vienne). When the 356 campaigning season began, he risked ambush by taking a heavily wooded route with some cavalry to relieve Autun, which was being assailed by a large barbarian force. The surprised German attackers took flight. Julian then assembled his whole army at Rheims, under his deputy, the magister equitum Marcellus. From there he set out to retake the critical lower Rhine city of Cologne, and its fortress across the river at Divitia (Deutz), built by Constantine the Great. Beating off a major German ambush along the way, his forces recaptured Cologne. Julian then concluded a peace treaty with the Franks.^[30] This had the important effect of cutting the opposition in half and allowing Julian to focus his resources on dealing with the Alamanni.

For the winter of 356/7, he chose Senones (Sens) near Paris as his base, but quartered some troops in other towns to spread the burden. A large band of Alamanni heard of his reduced escort, however, and besieged him at Sens. Julian's forces were able to hold out until, after a month, the Germans withdrew. He was so outnumbered by the enemy, however, that he was unable to sally forth and offer battle. The same factor may have prevented his magister equitum Marcellus at nearby Remi (Rheims) from attempting to relieve him, a failure criticised by Ammianus.^[31] In any event, Marcellus was dismissed from his post by Constantius and replaced by Severus, a distinguished officer who was more compatible with Julian.^[32]

For the 357 campaign season, a plan was laid down at Constantius' headquarters in Mediolanum (Milan) to trap the Alamanni in eastern Gaul in a pincer movement. Julian would advance eastward from Rheims, while part of Constantius' comitatus in Italy (25,000 strong) was despatched under magister peditum Barbatio to Augusta Rauracorum (Augst) in Raetia. The Alamanni bands would be cornered and destroyed in the southern part of Germania I province (Alsace).^[33]

But the main body of Alamanni, instead of trying to escape the Roman pincer movement by retreating across the Rhine, showed their contempt for the Roman army by invading and ravaging the Rhone valley, even trying to take the major city of Lugdunum (Lyon) by assault. The attack was repulsed as the walls of the city proved too strong.^[34] But although they had taken vast amounts of booty, the Alamanni were now trapped in the interior of Gaul with their way back to the Rhine barred by the Roman armies.

But part of the German force escaped. In Julian's sector, they were duly intercepted and destroyed by squadrons of cavalry sent by the Caesar to lie in ambush on three highways. But in Barbatio's sector, the Germans were allowed to pass unmolested by Barbatio's magister equitum Cella, who refused to authorise the cavalry commanders Valentinian (later emperor Valentinian I ruled 364-5) and Bainobaudes to deploy on a highway that they were sure the enemy would use.^[35] Nevertheless, Julian pursued them vigorously, surprising one group by crossing the Rhine, which had become passable at some points due to summer drought and slaughtering many. The Germans beyond the Rhine offered Julian no resistance, but took refuge in forests and swamps, allowing Julian to burn their villages and crops unhindered. They eventually sued for peace.^[36]

Julian now turned his attention to rebuilding the fortress at Saverne, which had been destroyed by the Alamanni. Saverne lay astride the Divodurum (Metz) - Strasbourg Roman highway, at the mouth of the main entry route through the Vosges mountains into northern Alsace. Its strategic location, and commanding heights overlooking the Rhine valley, explains why it was a priority for Julian. While this work was proceeding, Barbatio's army was attacked just outside Severus' camp by a large barbarian force. Instead of fighting, Barbatio's men fled and were pursued as far Augst. At this point, Barbatio, whose cooperation with Julian had been grudging at best, withdrew his army from Gaul altogether without Julian's permission, sending his forces into winter quarters in Italy, even though the Alamanni were far from ejected from Alsace or beaten.^[37] This left Julian exposed, with only 13,000 men.^[38]

The Alamanni confederation appears to have been under the presidency of two paramount kings, Chnodomar and Westralp. But Chnodomar was the driving force. A man of prodigious stature, strength and energy, he was nicknamed Gigas ("the Giant") by the Romans.^[39] He was a formidable sight in his "flashing" helmet (probably gold-leafed) and full parade armour. He is described by Ammianus as the "evil genius" behind the invasion of Gaul.^[40]

Chnodomar could not ignore Julian's fortification of Saverne, as it threatened his control of Alsace and blocked his main access route into the interior of Gaul. He had come to see this region as Alamanni territory by right of conquest after occupying it for several years. He claimed to possess letters from Constantius granting the Alamanni the right to occupy those lands.^[41] Chnodomar had been surprised and dismayed by Julian's successful campaigns of 355-7. But he was encouraged by his success against Barbatio and the intelligence brought to him by a deserter that Barbatio's withdrawal had left the Caesar with a relatively small force.^[42] Having defeated two Roman magistri equitum (Decentius and Barbatio) in the field, Chnodomar had lost the barbarians' traditional fear of pitched battles with the Romans.^[43]

The Alamanni high kings now ordered a mass mobilisation of all the confederation's member tribes. They gathered their disparate bands (of which there were at least seven, judging by the names of their kings given by Ammianus) at Strasbourg on the Rhine (about 32km SE of Saverne), a combined force of some 35,000 men.^[44] This appears to have been roughly the maximum force the Alamanni could muster.^[45] Their aim was to bring Julian to battle and crush him by sheer weight of numbers. They provoked Julian by sending him an insolent ultimatum to evacuate Alsace immediately.^[46]

Julian was now faced with a finely-balanced judgement call. The safer option was to ignore Chnodomar's challenge and to keep his forces in their fortified bases and request and await reinforcements, if necessary until the following year's campaign season. But the performance of Barbatio and the imperial comitatus in the recent campaign cast doubt on whether such reinforcements would be supplied and on their value if they were. Such a course would also expose Gaul to a massive Germanic invasion just when the harvest was due. Alternatively, he could fight Chnodomar alone. This offered the prospect of a decisive victory, since the Alamanni forces were now, unusually, concentrated and not divided into several bands. This argument was strongly made by Florentius, the praetorian prefect for Gaul, who was responsible for supplying the army.^[47] The Romans almost always won pitched battles with barbarians, because of their superior equipment, organisation and training.^[48] But in this case it was clearly a high-risk option because of the Germans' 3 to 1 superiority in numbers. If Julian lost, all his work in restoring the frontier would be undone and Gaul would be wide open to Germanic invasion, as it had been during the civil war.

Julian opted for battle. In this he was influenced by the fact that his force, although relatively small, was of high quality, containing some of the best regiments in the Late Roman army, with an awesome combat reputation.^[49] All were palatini (top-grade regiments). In addition, the same troops were eager for battle and loudly exhorted their Caesar, in whom they had developed complete confidence, to lead them into the fray.^[50]

[edit] Tactics

A deserter from the Scutarii regiment informed Chnodomar of Julian's plan to march to Strasbourg. Chnodomar thus had the advantage that he could choose the battlefield. He selected a low plateau of agricultural fields a few miles from the Rhine. Libanius adds the detail that on the German right wing was swampy ground traversed by an "elevated water-course", probably an aqueduct or canal.^[51] The most likely location of the battlefield is in Koenigshoffen, a western suburb of modern Strasbourg, at that time well outside, but within sight of, the Roman city. Here, the Roman highway from Saverne, whose course is today overlain by the modern D228 road from the village of Kuttolsheim to Strasbourg, made a sharp turn eastwards towards the Roman city.^[52]

Chnodomar's chief tactical concern was the superiority of the Roman cavalry. The size of his own cavalry is unknown, but was probably a small proportion of the total, as the Alamanni's heavily forested land was not suited to large-scale horse breeding.^[53] It may not greatly have outnumbered the Roman horse (3,000). In addition, Chnodomar's cavalry generally lacked body armour and helmets, although shields were more common.^[54] In contrast, the Romans not only deployed light, unarmoured cavalry like the Germans', but also semi-armoured (with mail cuirass) and heavily-armoured cavalry. The latter were called cataphracti. These were covered neck to toe in scale and/or lamellar articulated armour and were armed with a contus, a long heavy lance. It is unclear what proportion of the total cavalry were cataphracti, but since Ammianus mentions them only, they may have been as many as half (1,500). The lack of armour made the Germans vulnerable to the Romans in a mêlée, especially to the cataphracti. In addition, Chnodomar's cavalry, which was largely made up of young noblemen, was brave and effective.^[55] But the Roman cavalry was far better trained and disciplined, capable of large-scale formation manoeuvres which the Germans could not match.

To deal with this problem, Chnodomar selected a battlefield that minimised the advantages enjoyed by the Roman cavalry. His right flank was protected by woods in broken ground, effectively impassable to cavalry. To deal with the cataphracti threat on his left, he devised a stratagem. He interspersed lightly-armed infantry among his cavalry. The idea was that in a melee, the foot soldiers would bring down the cataphracti by stabbing their horses in the flanks, which were unprotected. The dismounted riders, weighed down by their armour, could be easily despatched.^[56]

The same deficiencies in armour and training affected Chnodomar's foot warriors.^[57] But he was confident his superiority in numbers would more than compensate. To improve the odds, he set up an ambush by hiding a large force in the woods on his right wing.^[58] These presumably were directed to wait for a good opportunity to surprise the Roman left wing.

[edit] Battle

Shield emblem of the late Roman legion Ioviani seniores. from the Notitia Dignitatum (late 4th c.)

The campaigning season was by now well-advanced, as Julian had spent a considerable time restoring Saverne. But it was still summer, as the weather was hot and wheat was ripe in the fields. It was therefore probably late August/early September. Julian's army marched 21 Roman miles (32km) from Saverne towards Strasbourg along the Metz - Strasbourg highway, arriving within reach of the enemy at around noon. Chnodomar, alerted by his lookouts that the Roman army was in sight, moved his army forward from its base before the ruined walls of Strasbourg to his chosen battlefield nearby.

A short distance from the battlefield, Julian called a halt for rest and refreshment. Concerned that his men might be too tired to fight after a long march in the hot sun, he proposed to make camp and postpone the clash until the following day. But his officers and men would have none of it and clamoured to be led against the enemy that same day. Julian, who prided himself on acting by consensus, gave way.^[59]

The German host was drawn up, likely in a dense mass, with the German left wing held by Chnodomar and his cavalry and the right wing astride the highway, their flank protected by woods, under his nephew Serapio (who was given his Greek name by his Hellenophile father).^[60][61] The rest of the line was under five major kings and ten petty kings.^[62] On the German right flank, beyond the highway, was wooded ground broken up by ditches. In these, Chnodomar concealed troops in ambush.

The Roman order of battle was a traditional array of infantry in the centre (drawn up in two lines, front and rear, spaced widely apart) and the cavalry (of unknown size, but, by implication, not more than c3,000) on the flank.^[63] In this case all the cavalry was stationed on the right flank, as the left flank as mentioned was impassable to cavalry. On this side, beside the highway, Julian stationed a separate division of perhaps 1,000 men under his second-in-command Severus.^[64] This division was probably ordered to move stealthily through the wooded area so as to surprise the Germans in the rear.

As soon as the two armies were drawn up, a clamour arose from the German ranks, loudly demanding that Chnodomar and his entourage of chiefs should dismount and lead the main body of German foot warriors from the front. Chnodomar and the chiefs immediately complied.^[65]

The Roman cavalry engaged the German horsemen, but Chnodomar's stratagem paid dividends. The interspersed foot warriors wreaked havoc, bringing down the horses of the cataphracti and then killing their riders on the ground. Disconcerted by these tactics, the Roman cavalry panicked and fled the field. In their panic, the cataphracti crashed into the Roman infantry on the right, which only held steady because of the skill of the crack auxilia palatina regiments Cornuti and Brachiati posted there. The Roman cavalry took refuge behind the infantry lines, where it took the personal intervention of Julian himself to rally them.^[66] This was the first critical moment, as the Roman front line's right flank was now exposed to assault by the victorious German cavalry. But the right wing, reinforced by the Regii and Batavi regiments, which moved forward from the right wing of the rear line, held formation. Together, these regiments managed to defend the Roman right wing until the regrouped Roman cavalry returned to relieve the pressure on the flank.^[67]

In the meantime, on the Roman left wing, Severus must have suspected the prepared ambush, and held back from advancing into the woods.^[68] Ammianus does not report further action in this sector. But it is likely that the hidden Germans eventually lost patience and advanced out of the woods and charged at Severus' division.^[69]

In the centre, the German foot warriors repeatedly charged straight at the serried ranks of Romans, hoping to break through by sheer weight of numbers. But the Roman front line held for a long time, inflicting severe casualties on the Germans who flung themselves recklessly at the massed spears. Then, the spearhead group of German chiefs and their best warriors succeeded, by desperate efforts, in punching a hole through the centre of the Roman front line.^[70] This was potentially disastrous for the Romans. But despite being cut in two, the Roman evidently front line did not collapse: the experienced frontline regiments managed to hold their separated wings in formation.

Meanwhile, a large number of Germans poured through the breach and charged the centre of the Roman rear line. This position was held by the elite Primani legion, which stopped the German attack in its tracks and then counterattacked, routing the breakthrough.^[71] The breach in the front line was presumably filled, either by the separated wings of the front line reconnecting, or by the Primani from the rear line (Ammianus does not specify which). The front line, now extended on the left flank by the rear line left wing, (and presumably by Severus' victorious division), began pushing the Germans back, and gradually hemmed them in from the flanks. At this point, the Germans were already exhausted and demoralised by their lack of progress and severe losses. The mass of their army was now trapped in an ever-tighter Roman crescent, with the troops on the edges being methodically cut down and the ones in the middle packed tightly together and unable to move. Finally, after more relentless pressure from the Romans, the German line collapsed: as panic spread through their ranks, the Germans broke formation and ran for their lives.^[72] Many did not run fast enough: pursued all the way to the Rhine by Roman cavalry and infantry, many were cut down as they ran. Large numbers attempted to swim across the river, but most drowned, hit by Roman missiles or weighed down by their armour.^[73]

Ammianus reports that 6,000 Germans perished on the battlefield and in the pursuit on land (Libanius gives a figure of 8,000).^[74] Thousands more drowned as they tried to get across the river. The Romans lost just 243 men, including four tribuni (regimental commanders) of which two were commanders of cataphracti.^[75] Chnodomar himself and an escort of 200 men tried to escape by reaching some boats prepared for just such an emergency near the wrecked Roman fort of Concordia (Lauterbourg), some 40 km downstream from Strasbourg. But they were cornered by a Roman cavalry squadron in a wood on the bank of the Rhine and surrendered. Brought before Julian, whom he begged for mercy, Chnodomar was sent on to the court of Constantius at Milan. He died of disease in a camp for barbarian prisoners in Rome.^[76]

After the battle, Julian was acclaimed as Augustus (emperor) by his troops. But he vehemently refused the title, which could only legally be bestowed by the ruling Augustus, Constantius.^[77] Given the latter's murderous attitude against potential contenders, Julian's caution is understandable.

[edit] Aftermath

View of Bingen am Rhein. This town, where the Nahe river joins the Rhine, was on the border between Germania I (ex Germania Superior) and Germania II (ex Germania Inferior) provinces. The Roman fort at this strategic site was repaired by Julian in 359 AD

The battle was the turning point in Julian's effort to restore the Rhine frontier. Until then, Julian was obliged to campaign largely inside Gaul, with the barbarian bands holding the initiative, playing cat-and-mouse with his forces and causing enormous economic damage to a vital region of the empire. Starting with the 358 campaigning season, Julian was able to take the war to the enemy, each year invading the lands beyond the Rhine, devastating them and forcing the tribes to accept tributary status. At the same time, he was able to make serious progress in repairing Rome's shattered line of forts. In Luttwakian terms, he was able to return to a strategy of "forward defence" after being obliged by circumstances to engage in defence-in-depth for three years.

Still in 357, Julian followed up the battle by an incursion into Alamanni territory beyond the Rhine. After ravaging the lands far and wide, he set about rebuilding a fort in the Agri Decumates (Black Forest) originally built by Trajan in the early 2nd century. He then granted the anxious barbarians a 10-month truce.^[78]

In 358, Julian first turned his attention to the Frankish tribes, crossing the lower Rhine and forced the Salii and Chamavi tribes to surrender and become tributarii (tribute-payers).^[79] He then restored three important forts on the lower Meuse river.^[80] Finally, he switched his attention to the Alamanni, crossing the Rhine at Mainz and forcing the submission of the new paramount kings Hortarius and Surmarius.^[81]

In 359, Julian restored seven forts and town walls in the middle Rhine, including Bonna (Bonn) and Bingium (Bingen), obliging his new tributary Alamanni to provide the supplies and labour needed. He then crossed the Rhine, marched through the territory of the tributaries and devastated the lands of the more remote kings who had fought at Strasbourg, including Westralp. All were forced to submit and return the thousands of Roman civilians they had captured and enslaved during the years of easy plunder.^[82]

In 360, his final campaigning season in Gaul, Julian was again proclaimed Augustus by his troops. He again refused, but this time, the troops insisted, making it clear they would mutiny and march against Constantius. Alarmed, but also secretly pleased, Julian wrote an apologetic letter to Constantius explaining why he had felt it necessary to bow to his soldiers' wishes and asking for his ratification. But Constantius replied demanding that Julian revert to Caesar status.^[83] Julian ignored the order, but in order to prove his good faith and also to keep his near-mutinous troops occupied, he crossed the Rhine and attacked the Attuarii tribe of the Frankish confederation.^[84] The following year, the two emperors marched against each other to settle the issue. But the empire was spared another civil war by the senior emperor's sudden death in Asia Minor (361).

As sole emperor (361-3), Julian succumbed, as so Roman leaders before him (Crassus, Trajan, Septimius Severus) to "Alexander the Great syndrome": the desire to emulate the Macedonian general and conquer the Persian empire. He invaded Mesopotamia at the head of an enormous army of 65,000. But the campaign was a disaster: Julian lost his own life and his army was forced to retreat with huge losses. Although most of these would have been from the eastern comitatus and from the emperor's own escort army, the comitatus of Illyricum and Gaul would undoubtedly have been stripped of troops to fill the gaps. The result was that Gaul was again overrun by Alamanni hordes and Julian's painstaking work of restoration undone. This forced Julian's successor, Valentinian I, to spend years carrying out a replay of Julian's Gallic campaign.

[edit] Roman order of battle

Shield emblem of the Heruli auxilia palatina regiment. From the Notitia Dignitatum

Shield emblem of the Petulantes auxilia palatina regiment. From the Notitia Dignitatum

The composition of Julian's army at Strasbourg can only be partially reconstructed. Ammianus gives the names of only five regiments in his account of the battle itself. But at other points of Ammianus' narrative of Julian's campaigns in Gaul, and also in Zosimus' history, there are mentions of other regiments in his comitatus, which were very likely at Strasbourg also.

A comitatus at this time probably contained only three types of regiment, all of them of the top, palatini, grade: cavalry vexillationes and infantry legiones and auxilia.^[85] There is much uncertainty about the size of late Roman army units. The official strength of vexillationes and legiones seems to have been 800 and 1,200 respectively. But actual strength recorded were 400 and 800 respectively.^[86] A midpoint between these figures is assumed here of 500 for vexillationes and 1,000 for legiones. The strength of the auxilia regiments is disputed: they may have been as large as legions, or only half the size.^[87] Half the size is more likely, as it accords with the size of this type of regiment's predecessor in the Principate, the auxiliary cohort.

The sources give the following units for Julian's comitatus:

NOTE: Asterisk indicates unit specified by Ammianus at Strasbourg

If all these units were present at Strasbourg, the infantry total is 1,000 short, probably the missing names of 2 auxilia regiments. It is therefore likely that Julian's force at Strasbourg consisted of 6 legiones and 8 auxilia of infantry and 6 vexillationes of cavalry.

As regards cavalry, Ammianus mentions only cataphracti in his account of the battle. But it is virtually certain that they were only part of his force. In the late army as a whole, only 15% of cavalry regiments were heavily armoured cataphracti.^[106] These were suitable for the shock charge. Two tribuni (regimental commanders) of cataphracts were reported killed at Strasbourg.^[107] There were thus at least two vexillationes of cataphracts (1,000 horse) engaged. Elsewhere in Ammianus and Zosimus it is stated that Julian had a schola of Gentiles and a regiment of scutarii under his command. Both these were normal (semi-armoured) units that represented the large majority (61%) of the late army's cavalry and were best suited to mêlée combat. There is also mention of light (unarmoured) units of equites Dalmatae and equites sagittarii (mounted archers). Light cavalry was used for harassment and pursuit. The likeliest scenario is that all these were present at Strasbourg, with 2 vexillationes each of heavy, normal and light cavalry engaged. It is thus likely that cataphracts were a third of Julian's cavalry at Strasbourg, but since Ammianus mentions only them, it is not impossible that there was an additional regiment bringing them up to half.

As regards the line of battle, we are given little information by Ammianus. He reports that the right wings of each line, front and rear, were held by 2 auxilia regiments and the centre of the rear line was held by the Primani legion. This is consistent with the ancient Roman custom, dating from the Republic, that the centre of the line was always held by the legions, the wings by the auxilia. Goldsworthy assumes that the two lines were equal in strength.^[108] If this was actually the case, then it is likely that each line's centre was held by 3 legions, and each line's wing by 2 auxilia regiments (Batavi and Regii on the right of the rear line, Cornuti and Brachiati on the right of thr frontline). There were thus 5,000 men in each line. However, this line-up does not leave any regiments for Severus' separate division on the left flank. But Severus' division may have been additional to Julian's 13,000 men, as it is mentioned as having its own separate camp.^[109] Alternatively, the rear (reserve) line may have been smaller than the front line, with 2 legions in the centre, sparing one legion (1,000 men) for Severus.

[edit] Citations

[edit] References

[edit] Ancient

• Ammianus Marcellinus Res Gestae (late 4th c.)
• Libanius Funeral Oration for Julian (mid 4th c.)
• Zosimus Nova Historia (late 5th c.)

[edit] Modern

• Elton, Hugh (1996), Roman Warfare 350-425
• Goldsworthy, Adrian (2000), Roman Warfare
• Jones, A. H. M. (1964), Later Roman Empire

[edit] Bibliography

• Karlheinz Fuchs, Martin Kempa, Rainer Redies: Die Alamannen, Theiss Verlag, Stuttgart 2001, ISBN 3-8062-1535-9. Ausstellungskatalog
• Dieter Geuenich: Geschichte der Alemannen, Verlag Kohlhammer, Stuttgart 2004, ISBN 3-17-018227-7/ISBN 3-17-012095-6.

[edit] See also

Late Roman army