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Nov. 30, 2019

26 – The Gallic Empire

26 – The Gallic Empire

Rome is falling apart. It's being invaded along its entire northern and eastern borders. Emperors are assassinated. Usurper generals rise up every year to seize power. Plague devastates the empire. Out of this chaos a Gallic military commander decides to create a new Celtic empire and revive a free Gaul.


It is hard to describe the state of the Roman Empire in the year 235. On the one hand, it had everything it needed to prosper. The Mediterranean Sea was an incredible highway for the transportation of goods and people and it was entirely controlled by Rome. The empire’s vastness meant it didn’t lack any necessary resources, and its large population meant it had enough people to harvest, work and defend the empire. Its infrastructure was among the world’s best and its technological innovation exceeded all of its rivals. If we looked at Rome from a God’s eye view in 235 we would probably expect it to prosper. Yet, there was a rot at the heart of the Roman world. The death of Alexander Severus meant the end of civilian rule. His execution by his own soldiers began the Crisis of the Third Century, wherein Rome had on average a new emperor every three years from 235 to 284.

During this period Rome was dominated by Barracks Emperors. Before the Crisis, the central Roman government was a constructive force that spent resources to grow the empire. Under the Barracks Emperors the central government was a massive drain on the empire as it requisitioned money, taxes, labor and other resources from its struggling provinces in order to pay the army. As economic conditions worsened the legions demanded pay increases and privileges…which worsened economic conditions as the provinces were overtaxed. When emperors tried to rein in the army for the benefit of the provinces the army deposed them, leading to civil war…which further damaged the economy. This in turn led to the legions demanding more pay so they could care for themselves in the face of rising inflation and you see where this is going. Emperors could only come to power by bribing the legions with massive bonuses, but once in power emperors had to come to grips with the unsustainability of their policies. The same organization that put emperors in power was economically ravaging the empire while simultaneously making the normal functioning of government administration impossible.

The central government ran massive deficits, leading to hyperinflation, which crippled internal trade. From Nero to Alexander Severus the silver content of denarius decreased from 100% to 50%. As historian Mary Boatwright notes, “By the late third-century, some denarii were simply silver-plated copper coins.” Between the reign of Antoninus Pius and the end of the third century, one modius of wheat, or roughly two gallons, increased from two sesterces to 400. This 200-fold increase is astounding even for modern times, but in ancient and medieval societies inflation was usually negligible except in times of crisis.

As usurper general after usurper general rose and became emperor the military became more preoccupied with civil insurrection than guarding the frontiers. This was especially problematic because Rome faced three major threats. The Sassanid Persians ravaged Syria and the far east. Goths poured across the Danube into Dacia and the Balkans. Meanwhile large German tribes with experienced armies threatened the Rhine. Increasingly localities had to protect themselves by building city walls and raising local militia. This meant that localities increasingly viewed the central government as negligent or even a threat to their security.

Culturally, the empire rapidly decentralized. The central government spent far less on construction projects, festivals and games. The cult worship of the emperor and the city of Rome was perennially underfunded. But perhaps the most important shift occurred within the legions themselves. Keep in mind, the legions were the primary force for Romanization across the world, through conquest but also because they brought with them Latin and Italian customs wherever they went. During Trajan’s reign in the early 2nd century the majority of legionaries were not primarily Italian. Then the Antonine Plague hit Italy and Rome itself, particularly hard. During the Crisis of the Third Century a twenty-year-long plague broke out in Italy, and some sources claimed 5,000 Romans died a day. Rome’s population dropped below one million for the first time since perhaps 100 BCE, and may have been as low as 500,000 by the end of the Crisis. Fewer Italian conscripts were spreading Roman cultural practices, ideas and the Latin language. This meant provinces de-romanized, as in the case with Gallia, which experienced a resurgence of the Celtic language and cultural practices. The Roman Empire was not breaking apart just yet, but it was devolving as the provinces drifted apart economically, culturally and linguistically. But the empire was still held together by political tradition and the power of the emperors.

The power of the emperors reached an absolute nadir under Valerian. Valerian ruled for seven years, the last of which was spent fighting the Sassanid Persians. While the Sassanids developed new military techniques and strategies, the Roman legions had not innovated in a long time. Consistent success for hundreds of years dissuaded Roman generals from experimenting with new styles of warfare, even as the Germans, Goths and Sassanids learned Roman styles and adapted to them. In 260, Valerian engaged a Persian army at the Battle of Edessa, in what is today southeastern Turkey. There, the Persians smashed a large Roman army and captured the emperor. This was the first time a Roman emperor was held prisoner by a foreign power. This devastated Roman confidence in emperors as god-rulers. Furthermore, Valerian’s son and successor, Gallienus, couldn’t rescue or avenge his father because he was busy fighting numerous usurper generals.

At this time Gallia suffered repeated German incursions. From 253-onward Germans repeatedly crossed the Rhine or sailed west along the coast into Gallia where they raided, pillaged and even conquered territory. Two major tribes assaulted Gallia. Along the southern half of the Rhine were the Alemanni. But even more dangerous were a new group of Germans called the Franks, who were crossing the northern half of the Rhine into Germania Inferior and northeastern Gallia. The Franks were first mentioned by Roman sources in 257. We know very little about their early history since they left no written sources. Furthermore, this period of frequent migration and war means there are relatively few surviving artifacts. Some modern archeologists and historians postulate that the Franks may have been a conglomeration of earlier tribes, including the Chatti, Batavi, Sugambri and Bructeri. Just as the Celts had conquered Gaul and forced their culture, language and identity on the population, it is likely that the Franks did the same to many of their fellow Germans. Furthermore, smaller German tribes may have willingly joined a Frankish coalition as protection against other large German tribes such as the Alemanni.

The Franks were very unlike their Alemanni cousins in that they were master sailors, which allowed them to easily bypass the Roman fortifications on the Rhine border. From the mid-3rd century onward many Franks sailed into northern Gallia where they raided, pillaged or even settled. From there many sailed to Britannia. In 260 a group of Franks raided Iberia and even proceeded into Africa. The Gauls were horrified that after centuries their borders were no longer secure as Franks raided or settled their lands with little resistance. Many must have felt abandoned as the emperors were fighting in the east. When word arrived that Valerian was captured many in the Gallic aristocracy believed that Rome was on its deathbed.

After Valerian was captured, his son Gallienus became sole emperor. Gallienus had to rally the east against the Persians, while coordinating a defense against raiders in the Black Sea. Simultaneously, a usurper general in Pannonia saw his chance to seize the empire while Gallienus was in the far east and had the legions declare him emperor. Gallienus was trapped between the Persians and a rebel army, and as far from Gallia as possible, which allowed Marcus Cassianus Latinius Postumus, the governor of Germania Inferior and Germania Superior, to make his move.

Postumus was probably born somewhere in German Inferior or Belgica in the second half of the 3rd century. His family was probably a mixture of Batavi and Gauls. Most of the old aristocracy in Gallia was in its center, notably at Lugdunum, meaning Postumus was probably born to a family in the lower echelons of the aristocracy. This doesn’t mean they were without means, however. While the center of Gallia was declining the frontiers were growing, so it is possible that Postumus’ family was wealthy but without the illustrious pedigree of the more-established Gauls. We can’t know for sure since records are scarce during this period, though demographic and economic trends make this likely. If this is the case, then Postumus’ position may be analogous to the ‘novo homo’ in the Roman Republic; he was an ambitious man with significant means but was looked down upon by the old aristocracy.

Postumus joined the military and made his way up the ranks becoming a competent commander who had frequent experience combatting the German invaders during the mid-3rd century. When Valerian was captured, his son Gallienus gave Postumus command of the western empire. In 260 a German army raided northern Italy, but as they were returning to Germania Postumus cornered and annihilated them. Postumus then gave the captured wealth to his troops, in an act that looked a lot like second-hand looting to many Roman officials. These officials counseled Saloninus, Gallienus’ son and heir, to demand Postumus reclaim the booty from his soldiers and deliver it to him at Colonia Agrippina, modern-day Cologne. Postumus very clearly understood that taking treasure from Roman soldiers was a good way to get killed, even if that treasure was ill-gotten. Postumus marched his army to Colonia Agrippina and when he arrived he essentially turned to the troops and said, “Saloninus, the bureaucrat son of a struggling emperor and grandson of a disgraced and captured emperor, has ordered me to take away the spoils of war you rightfully won. I disagree with this order…if only there was something I could do.” The soldiers took the hint and they besieged the city. After brief fighting Saloninus and his advisers were executed and the legions declared Postumus their emperor.

Normally when a military commander is declared emperor they march on Rome, which was still wealthy, populous, and housed the Senate, all of which gave whoever controlled the city an advantage over rival claimants. But Postumus did a strange thing; he did not march on the Eternal City. Historians have debated why this was, and since few records remain we can only speculate. Possibly the reason why he didn’t’ march on Rome was because he knew just how dire Gallia’s border situation was. Germans had increasingly raided and even settled from the Atlantic coast all the way to the Alps. Postumus couldn’t afford to campaign against the rest of the empire because the second he removed a large number of his forces then the floodgates would open to German invasion. Instead, Postumus decided that he was going to create his own empire, dubbed the Imperium Galliarum, the Gallic Empire.

Postumus’ empire included the two German provinces Germania Superior and Germania Inferior, Belgica and all of Gallia except for Gallia Narbonensis in the south. Additionally, Hispania hailed him as their emperor, though it retained its autonomy. It’s also likely that Raetia, or modern-say Switzerland, initially submitted to Postumus in recognition of his deeds fighting Germans along the Alps. Postumus then declared a new capital at Augusta Trevitorium, or modern-day Trier. There he created a new Praetorian Guard and a senate, which was staffed by the Gallic aristocracy. Thus, the political structure was a near-copy of Rome. Yet, Postumus recognized that the Gauls were disillusioned with Rome and so he styled himself as the restorer of a free Gaul. Gallia was already de-romanizing, but now it had a leader that extolled Celtic culture.

Postumus was an incredibly effective ruler who assuaged or even fixed many of his empire’s problems. First, he aggressively defended the borders from further German invasion. Next, he issued new coins to replace the virtually worthless Roman coins which spurred confidence in the economy and led to economic revival. Postumus was so successful that he made a trip to Britannia, probably at the head of an army, and was hailed as emperor there.

Meanwhile, Gallienus had put down at least 3 usurper generals and reasserted control of the rest of the Roman Empire by 265 and decided it was time to reconquer the western provinces. Postumus tried to negotiate with Gallienus and claimed that he was only doing what was best for Rome by securing the German border, but Gallienus could never forgive Postumus for murdering his son and launched an invasion of Gallia. Gallienus pushed back Postumus’ forces, but he was hit by an arrow and had to abandon the campaign. After he recovered, Gallienus continued the fight and pressed into Gallia. Just as things looked hopeless for Postumus, Gallienus was betrayed by his cavalry commander, who was angry at a recent demotion. This defection forced Gallienus back into Italy, where he was assassinated in 268. Postumus held on to his empire, only losing the relatively unimportant province of Raetia in the process.

By the end of 268 Postumus looked like he was about to create a successful new Romano-Celtic empire in the West. The borders were secure, the economy was rebounding, and he had successfully repulsed a Roman invasion. Yet, the Gallic Empire suffered from the same treacherous political scheming of Rome. In 269 a usurper general was declared emperor in Mogontiacum, modern-day Mainz, along the Rhine. Postumus assembled his armies and besieged the city and after five months the usurper general was killed in the fighting. But then Postumus’ legions demanded the right to sack the city. Postumus couldn’t allow his own people to be raped, slaughtered and their possessions stolen so he refused. In response, the legions executed him and proclaimed military commander Marcus Aurelius Marius their new emperor, whose first act was to allow them to sack the city. Postumus had succeeded beyond anyone’s wildest dreams in forging a new, cohesive empire that could stand up to both Germans and Rome. But after nine years he was killed by his own soldiers.

Emperor Marius marched on the Gallic capital of Trier to assume his lordship over the country and within a few months, he was assassinated by the Praetorian prefect Victorinus. Victorinus was born into the Gallic aristocracy and had been elevated to his position by Postumus, meaning he probably believed in Postumus’ mission to create a free Gallic empire and was loyal to him personally. Victorinus could not allow a usurper and a murderer to rule the empire, and assumed the role himself.

But despite Victorinus’ dreams of continuing Postumus’ legacy, the Gallic Empire rapidly unraveled under his rule. Hispania watched the double assassination, lost confidence in this new project and declared for the Roman emperor Claudius Gothicus. This was an immense blow since Hispania was a wealthy province whose mines were necessary for Gallia’s new coinage system. After Hispania left, Victorinus sent loyalists to southern Gallia to encourage fellow Gauls to abandon Rome and join the new empire but this was largely unsuccessful. Then Augustodunum (Autun), within the heart of Gallia, declared for Gothicus. Victorinus couldn’t allow central Gallia to revolt and he besieged the city. The siege was a success and the new emperor’s troops demanded the right to sack the city…which he allowed them. After all, he knew what happened the last time an emperor refused the savage demands of his legions. We can never know what Victorinus was thinking in that moment as one of the great Gallic cities went up in flames while the screams of women and children echoed out of the ruined walls. I imagine tears welled in his eyes as he realized that he was responsible for the desolation of his own people, or at the very least, he was helpless to stop it. To Victorinus the flames engulfing the city probably looked like an omen of the Gallic Empire’s ruin.

In 271, after two years as emperor, Victorinus met a cruel, though unexpected fate. One of his subcommanders believed he had been sleeping with his wife and assassinated him. After a brief period of chaos the army declared Tetricus, the governor of Gallia Aquitania, their emperor in the city of Burdigala (Bordeaux). Tetricus tried to continue Postumus’ legacy, but it quickly became clear no one but Postumus could have held the empire together. German raids became more frequent and Roman forts along the Rhine were overrun and abandoned. In 273 Tetricus crushed a revolt by a usurper general, which sapped more strength from his armies. Then in 274 the Roman Emperor Aurelian appeared with a massive army to reclaim the west.

Aurelian is one of the lesser-known great emperors of Rome. Self-titled the ‘Restorer of the World,’ Aurelian’s military conquests and reforms brought the provinces of Rome back under control. From 270 to 273 Aurelian won numerous victories against Gothic invaders and reconquered the far-eastern provinces which broke away. In 274 he marched into Gallia and met Tetricus at the Battle of Châlons. Tetricus was defeated, and he was taken to Rome and forced to march in a triumph, though afterwards Aurelian showed him mercy and even promoted him to the position of an administrator in Italy.

The Gallic Empire is a fascinating episode in the overall history of France. For three hundred years the Gauls lived under Roman rule and accepted Roman hegemony, believing that resistance to Rome was more trouble than it was worth. From the Antonine Plague to the Crisis of the Third Century the Gallic people rediscovered their heritage, at least partially. The elites often spoke Latin and used Roman law and custom, though the Gallic language, culture and Gallic gods revived as Latin influence waned. At the height of this crisis the Gauls tried to break free and if only Postumus had lived longer they might have established a lasting Romano-Celtic empire. But even if Postumus could revive a sort of proto-Gallic nationalism among the elite and the people at large, the army was fully Roman and demanded license to do whatever it wished. When Postumus died the empire’s sustainability died with him as none of his successors were as capable as he was. If the Gallic Empire hadn’t fallen to Aurelian it probably would have fallen to German invasion.

Gallia’s reentry into the Roman Empire was a disaster in the short-term. Many of its defenders had died fighting Aurelian. meaning new waves of Franks, Vandals and Burgundians entered the country. Furthermore, Aurelian was assassinated in 275, and Rome fell into another period of infighting, which further weakened the border. Gallia was in bad shape. It was beset by invaders and too weak to defend itself or revolt. But in Gallia’s darkest hour a new leader emerged. In 284 Diocletian became emperor, ended the Crisis of the Third Century and remade the empire into a great power.

As we end today’s episode we must ask the question: what impact did the Gallic Empire have on Gallia and Rome? Culturally, it didn’t have any long-lasting impact. While there was a greater emphasis placed on Gallic culture, the Romans reasserted their dominance. Moreover, more Germans were settling in Gallia and bringing with them their own culture, threatening the Celtic culture. All of the positive changes under Postumus were undone by the failure of his successors and the violent Roman reconquest. Yet, Postumus’ initial success showed a new path of survival for the empire. In a few short years Postumus routed the Germans and revived the economy. This incredible feat must have had an influence on Diocletian, who understood that the Roman Empire had become too unwieldy for any one ruler to control. This led him to create the Tetrarchy, which divided the Roman world between four emperors. Thus, even though Gallia could not escape the power of Rome, it created a blueprint for future Roman survival.




Ancient History Encyclopedia

Cassius Dio’s Roman History

Drinkwater, J.E., Roman Gaul, 1983

Heather, Peter, The Fall of the Roman Empire: A New History of Rome and the Barbarians, 2005.

Herodian’s History of the Empire from the Death of Marcus

Mary T. Boatwright, Daniel J. Gargola, and Richard J. A. Talbert, Romans: From Village to Empire, 2004.