BATTLE OF THE FRIGIDUS Field of Glory II Field of Glory II is a turn-based tactical game set during the Rise of Rome from 280 BC to 25 BC. Take command of a huge variety of armies employing vastly different tactical doctrines. Lead your chosen army and its generals to victory in set-piece historical battles.

The Fatal Blow to the Western Roman Armies

Date 5-6 September 394

Location Near the River Frigidus, modern River Vipava, western Slovenia


Why Frigidus and not Adrianople? Surely a `barbarian’ victory over the Roman army in Thrace should have been considered important (or decisive) enough for this study? The situation after the Battle of Adrianople (378) was, undoubtedly, disastrous for the empire: a Roman emperor had been killed in battle for the first time in over a century; there was a power vacuum in the East; and the Persian frontier was left largely bereft of troops, while the Goths were left roaming around Thrace, free to pillage and destroy. But the latter were inexperienced in besieging fortified cities, something which prevented them from taking advantage of the situation in order to establish themselves firmly in the eastern Balkans; they just had to contend with raiding the Thracian countryside.

The Roman historian Ammianus Marcellinus (died c. 391-400) compared Adrianople with Cannae (216bc), Hannibal’s great defeat of the Romans. However, the point about Cannae was that, horrific disaster that it was, Rome revived and won the war. That was the case for the period that followed Adrianople: Emperor Theodosius moved the Goths into the empire and enrolled them in the army as foederati (allies), following the treaty signed with them on 3 October 382. The `Gothic Crisis’ ended with a Roman victory over the remaining semi-independent Goths of the Balkans in 383.

Theodosius was appointed augustus in the East by Gratian, the augustus of the West, in January 379, after the political vacuum that followed the disastrous outcome of the Battle of Adrianople in August 378. In the Balkans, Theodosius was given the command of Dacia, Macedonia in eastern Illyricum. In 381, an army sent by Gratian and led by the `barbarian’ (Romanized Franks) generals Bauto and Arbogast drove the Goths out of Macedonia and Thessaly and back to Thrace. Gratian, however, was soon toppled and killed by the Spanish commander of Britain, Magnus Maximus, in August 383; the former had shown extensive favouritism to `barbarian’ soldiers, at the expense of his Roman troops. Gratian’s younger brother Valentinian, despite having been declared an heir to the throne of the West in 375, was only thirteen years old, and too young to exercise any independent power.

Following Maximus’ usurpation of the throne in the West, and by negotiation with Emperor Theodosius, Maximus was made emperor in Britannia and Gaul, with his base in the German city of Trier, while the young Valentinian retained Italy, Pannonia, Hispania and Africa, with his capital in Milan. However, Maximus’ ambitions led him to invade Italy in 387, displacing Valentinian who sought refuge in the eastern city of Thessaloniki; but Maximus was eventually defeated by Theodosius at the Battle of the Save in 388. The main reason behind Theodosius’ change of mind in supporting young Valentinian and his mother Justina was the fact that Justina offered Theodosius the prospect of marriage to her beautiful daughter Galla, hence achieving dynastic relations between East and West.

Valentinian II was dispatched to Trier in 388, where he remained under the control of Arbogast, the Frankish magister militum appointed by Theodosius. Contemporary primary sources portray the role played by Valentinian in Trier as that of a figurehead under the absolute control of Arbogast, who was the real power broker in the West. Both parties attempted to assert their power from each other; however, the (Romanized) Frankish general could not be crowned augustus, so he found a more `co-operative’ Roman aristocrat named Eugenius, a well-educated professor of rhetoric, who made a common cause with him.

But when Valentinian also attempted to break his bonds, he was soon found hanged, and Arbogast quickly proclaimed Eugenius as emperor. Arbogast’s action showed how political power in the West had fallen into the hands of Germans. But this was also a challenge to the augustus in the East who went too far, and Theodosius had to march west once more to re-establish order.


Preparations for the armed clash between Theodosius and Arbogast went on for a year and a half after Theodosius proclaimed his second son, Honorius, as augustus in the West, in January 393. The religious character of the conflict was pronounced when the eunuch Eutropius, one of Theodosius’ closest advisers, was dispatched from Constantinople with instructions to seek the wisdom of John of Lycopolis, an aged Christian monk living in the Egyptian town of Thebais. According to the account of the meeting given by Sozomen (c. 400-c. 450), the old monk prophesied that Theodosius would achieve a costly but decisive victory over the pagan Eugenius and Arbogast.

Theodosius’ expeditionary army departed from Constantinople sometime in May 394. The Eastern emperor himself led the army, having chosen renowned leaders to be among his commanders, namely Stilicho – the Vandal who later became the guardian of the under-age Honorius in the West – and Timasius, the Visigoth chieftains Gainas and Alaric, and a Caucasian Iberian (modern Georgian) named Bacurius Hiberius.

Theodosius’ advance through Pannonia until the Julian Alps was unopposed, and the troops took over a number of key mountain passages that led to the ancient Roman city of Aquileia, at the head of the Adriatic Sea. Based on his experience in fighting the usurper Magnus Maximus in Gaul, Arbogast had thought best to abandon Pannonia and concentrate his forces in northern Italy instead.

At the beginning of September, Theodosius’ army descended from the Alps unopposed, heading towards the valley of the Frigidus river to the east of Aquileia. It was in this narrow, mountainous region that they came upon the Western Roman army’s encampment on the banks of the Frigidus. Arbogast was careful to dispatch detachments of his army to hold every high point in the river valley, to hinder the Eastern army’s ability to manoeuvre freely.

We should bear in mind that the Battle of the Frigidus river took place between Castra and Ad Pirum, two of a series of interconnected Roman fortifications in southern Pannonia that defended the hilly and mountainous eastern approaches to the Italian peninsula; this system of fortifications was called Claustra Alpium Iuliarum (Latin for `Barrier of the Julian Alps’).


Deducing any numbers for the two armies that clashed on the banks of the Frigidus is a futile exercise. Nevertheless, perhaps as many as 20,000 Gothic foederati would have been raised by the Gothic leaders Gainas and Alaric, and these would have suffered the highest casualties among the troops from the Eastern armies during the two-day clash. There may even have been some Georgian troops in the ranks of Theodosius’ army, for a Georgian officer named Bacurius the Iberian is mentioned in chronicles of the time.

With Arbogast in charge of the Western army, he is very likely to have recruited large numbers of his fellow Gallo-Romans. But the bulk of the troops on both sides would have been Roman, although this is the period when legionaries were beginning to be outnumbered by auxiliaries. As in the Eastern army, cavalry was becoming a larger percentage of the overall number of the Western forces – but not quite in the numbers as in the East. Historians estimate that the Eastern and Western armies that faced each other at Frigidus would have been, more or less, of the same importance and size, in the range of 40,000-50,000 each.

The ‘Barrier of the Julian Alps’ was the mountainous and hilly region from the Julian Alps to the Kvarner Gulf, in modern Slovenia, a defensive system within the Roman Empire that protected Italy from possible invasions from the East.


The Roman soldiers who faced the `barbarian invasions’ of the fourth and fifth centuries carried weapons that varied little from those of the first-century legionnaires. However, the strategic emphasis that the Romans put on their cavalry forces in the fourth century brought about the gradual replacement of the short gladius, the traditional sword of the Roman legionary of the Antonine period (AD96 to AD192), by the spatha, a longer sword (up to 75cm long) traditionally used by the Roman cavalry to strike at enemy warriors on the ground. The spear or lance was the primary offensive weapon of the warriors of Antiquity, both cavalry and infantry, and while there is remarkably little evidence regarding the length of Roman spears, their size would have remained relatively consistent, between 2.4 and 2.7m.

There were three types of javelin: the shafted weapon identified as the speculum, consisting of a shaft 5.5 Roman feet long (1.63m) and a metal head 9 Roman inches long (200mm); the so-called verutum, consisting of a shaft some 3.5 Roman feet long (1.03m), which had a head of 9 Roman inches (200mm); and a third type, more like a throwing dart, called the plumbata or mattiobarbuli, less than one metre long and with a head averaging between 100 and 200mm.

The spear was also the primary weapon of the fourth- and fifth-century `barbarians’; it was called a frameae, and according to the first-century Roman author Tacitus, `had short and narrow blades, but so sharp and easy to handle that they can be used either at close quarters or in long-range fighting’. The only thing we can be sure about the `barbarian’ spears is the lack of uniformity in size or shape, with each smith probably creating their own design. Swords were equally important for the `barbarians’ as they were for the Romans, and findings from burial sites point to a variety of types, from longer ones (up to 100cm), to shorter ones (around 40-50cm).

Finally the axe was used by the early `barbarians’, both as a smashing weapon and a projectile. It remained largely in use until the early seventh century, and was adopted by the Romans already from the fourth century; a weapon such as the Frankish francisca weighed some 1.2kg, and it could drop an enemy at distances of between 4 to 15 metres.


While the average `barbarian’ warrior wore little, if no body armour, it was not unusual for chieftains to be in the possession of their own helmets and sophisticatedly decorated armour. They did, however, carry convex wooden shields made of strips of wood covered with leather, measuring between 80 to 90cm in diameter. Roman armour was, of course, much more elaborately designed and manufactured, although the sources of the period complain of many legionaries losing their armour and helmets and relying only on their shields for protection. How widespread this practice was, however, is impossible to determine.

Fourth-century Roman body armour was of two distinct types: the lorica squamata, a type of scale armour made of small scales made of iron, bronze, bone, wood, horn or leather sewn to a fabric backing; the other the lorica hamata, made of metal rings that were sewn in interlocking rows to a fabric backing. Roman round (or oval) shields had replaced the popular curved rectangular ones of the Antonine period around the turn of the third century, and were largely made of wood.

Finally, the simplest type of Roman helmet was the ridge one, composed of two pieces of metal joined together by a central metallic strip running from the brow to the back of the neck, usually rounded but often having a slightly raised top. It was fitted with neck guards and cheek fittings directly attached to the leather lining of the helmet. But even this ridge helmet would often have been discarded in favour of the `Pannonian helmet’, a leather cap, as Vegetius (c. AD400, author of the famous military treatise Epitoma Rei Militaris) informs us, worn by the legionaries under their iron helmet.


Regrettably, our sources do not mention anything about the formations of the opposing armies that lined up for battle in the evening of the 5 September. Hostilities commenced when Theodosius ordered his Visigoth foederati under Gainas and Alaric, who were deployed in the first line preceding the main division of the Romans, to launch a frontal attack against the enemy infantry across the battlefield. These Gothic troops were therefore sent into the battle more or less as `cannon fodder’, suffering some 10,000 casualties. The rest of the Eastern army then followed in a headlong attack that resulted in heavy casualties on both sides but little gain, with the Iberian commander Bacurius being killed in action.

We are left in the dark about which units followed up the Visigoth attack, but bearing in mind the late Roman army’s typical battlefield deployment, according to Vegetius, this would have included the deployment of the main units of Roman infantry in three lines in the centre of the formation, with skirmish troops placed in front of them to `soften up’ an enemy attack. The cavalry units would have been placed on the flanks, first to offer protection against any encircling manoeuvres, and to launch an attack against the enemy at the right moment. Therefore we can only assume that both the cavalry and the infantry units of the first lines would have clashed with Arbogast’s units on the first evening of the battle.

While Theodosius spent a sleepless night (5/6 September) praying to God, Western emperor Eugenius ordered a victory celebration in the army camp, sure that the next day the East Romans would be swept from the field. Arbogast was more cautious, however, and dispatched a detachment of élite troops – probably locals who knew the area – to march secretly through a footpath that led to the mountain passes behind the Eastern army’s camp, in order to block their retreat and attack them from the rear the following day. However, the commander of this detachment made contact with the Eastern Roman force, and defected to Theodosius after agreeing to a considerable monetary inducement.

This act of defection was viewed by the Eastern emperor as God’s answer to his prayers, prompting him to open the second day of hostilities with an all-out attack. The final `miracle’ came in the form of a weather phenomenon called a bora – a strong north to north-eastern wind that blows from the mountains to the sea, and an integral feature of Slovenia’s Vipava Valley. According to tradition, the storm blew directly into the eyes of the Western army, and was said to be so strong that it caused the javelins and arrows fired to be blown back towards them. At the least it disrupted the movements of Arbogast’s army, and when the East Romans charged, the Western Roman units rapidly disintegrated.


The Battle of the Frigidus has been represented as the triumph of Christianity over the last vestiges of paganism in the Western part of the Roman Empire. Contemporary sources attributed equal importance and glory to the outcome of the Battle of the Frigidus as had been given to the Battle of the Milvian Bridge eighty-two years earlier. Influential Christian writers of the period – such as Sozomen (c. 400-c. 450), Theodoret of Cyrrhus (c. 393-c. 458/466), and especially Rufinus, in his continuation of Eusebius’ Ecclesiastical History published in 402/3, paint a lavish portrait of Theodosius’ campaign against Eugenius and Arbogast, more or less as some sort of a proto-`Holy War’ to suppress the pagani.

Recently, however, Alan Cameron cast doubt on the truthfulness and the historical value of the contemporary Christian accounts with regard to the eye-witness reports of the battle, and how these were remembered. Rather, he asserted that these historical accounts have been distorted, based on political and theological considerations, to justify Theodosius’ campaign against Eugenius and Arbogast, who were falsely branded as pagans after their defeat. Eugenius was further painted as a `usurper’ (tyrannus), a term which after the reign of Constantine the Great in the fourth century had taken the additional meaning of persecutor of Christians, and – on top of that – as a person who was `by no means sincere in his profession of Christianity’: this was undoubtedly false, and gives us an idea of the blatant propaganda that emerges from the Christian accounts of the Battle of Frigidus!

This is further confirmed by the historical manipulation of the bora, the storm that blew in the second day of the battle. According to the same study, the earliest source to mention the decisive bora was Ambrose of Milan (c. 340-397), but he reports about the storm on the day before any fighting had begun. This could have been picked up by another contemporary source, the poet Claudian (c. 370-c. 404), who, in his propagandistic poetry, moved the wind to the decisive moment of the battle as a sign of godly approval of the emperor’s strategy. Therefore we should put the emphasis of Theodosius’ victory at Frigidus on the asserting of control over the Western parts of the empire and the slaughtering of the Western army, rather than on the overthrow of paganism. Considered in sequence with the earlier Battle of the Save (388), where the usurper Maximus was heavily defeated, the units that had been withdrawn from the north-western provinces of the Roman Empire to be used in the gamble for power between the Eastern and the Western augusti, lost heavily in the battles with Theodosius’ Eastern troops. Large parts of Gaul and the Rhine frontier were left on their own, as there was hardly any time for governmental structures to be reorganized after Maximus’ usurpation before troops were again withdrawn for Eugenius and Arbogast’s rebellion.

Thereafter the northern regions were seemingly left in a political limbo, while the Roman empire was contracting closer to the Mediterranean Sea.