The Huns march westward, pushing uncountable numbers of Germans towards Rome. The Romanized Franks have to defend Gaul while the empire crumbles. But the more successful the Franks are the more they realize Rome needs them more than they need it.
Today we’re going to move from the early 4th century into the early 5th century, from the end of Constantine’s reign to the devolution of Roman authority in Gaul. From Constantine’s death to the fall of the Western Roman Empire the Franks and Romans were involved in a long process where the former replaced the latter, as a people and as leaders, as Gaul transformed into the new Francia. This process was often violent, as Franks across the Rhine invaded Gaul every time Rome fell into civil wars. But the Franks were more often allies of the Romans against the Alemanni, Vandals, Saxons and later the Huns. They earned their place within Gallic society and the military, but corruption and incompetence from the Emperors frustrated the Franks. Rome was decrepit and decaying, while the Franks were strong, growing and capable. During the 4th century the Franks simultaneously fought against invaders from across the Rhine, and against Roman prejudice in order to earn their place as Romans. But by the late 5th century, the Franks increasingly abandoned the crumbling Rome for the new Francia taking shape west of the Rhine.
Constantine was arguably the last Roman Emperor capable of meeting the challenges his entire empire faced. Some future emperors would possess a great deal of military and bureaucratic skill, but after Constantine’s death ‘Rome’ that classical, Latin-speaking, Mediterranean civilization, was in terminal decline. This decline was already present during Constantine’s reign. The economy was in shambles, the border was porous, and non-Romans settled along the northern frontiers on the promise that they’d keep out more migrants even as many didn’t assimilate to Roman culture. Yet Constantine’s large and effective bureaucracy, his cult of personality as a hero of Christianity, and his sheer power demonstrated after winning numerous civil wars, kept the empire intact.
The first man in line to replace Constantine was his son Crispus who was born around the turn of the 4th century to Constantine’s first wife Minervina. Crispus was raised in Gaul among soldiers and took after his warlike father. In 317 Crispus was raised to the role of Caesar and given command of the legions in Gaul. Over the next six years he repeatedly warred against the Franks and the Alemanni, and proved a fierce warrior and a brilliant general. Crispus then served in the civil war between his father and Licinius in the East. When Constantine assumed sole emperorship in 324 it appeared as if Crispus would be his heir apparent, as his half-brothers were only 8, 7 and 1 years old.
But in 326 Constantine ordered his son’s execution and damned his memory, removing him, his wife and his son’s names and likeness from all official publications, statues and decrees. Historians still debate why this happened though the fact that Constantine executed and damned the memory of his second wife Fausta at the same time is very suspicious. It’s unlikely that the two were conspiring against Constantine since Crispus was the heir-apparent, and as empress Fausta reached the highest stage possible for her. More likely, the two were lovers, and when this was discovered Constantine executed and damned them in rage and humiliation. Whatever did occur between the two destroyed them both.
In the last years of his reign Constantine decided to divide administration of the empire between his three sons: Constantine II, Constantius II and Constans. Constantine was kind of full of himself, and a pretty bad father too. Since his sons were still relatively young he promoted two of his nephews to rule Pontus and Thrace, splitting the empire five ways. No one was acclaimed Caesar by the time of Constantine’s death on the 22 of May 337, leaving a split empire. But the army refused to recognize the two nephews and murdered them alongside all of the male descendants of Constantius I, Constantine’s father, sparing only the two young boys Gallus and Julian.
The empire was roughly split in three, with Constantine II ruling the West, Constans the center and Constantius II in the east. Constantine II was born in Arelate and raised in the barracks bordering Germania. When his brother Crispus was executed he became the commander of the Gallic armies at the age of ten and accompanied his generals in wars with the Alemanni. After his father’s death he received Gaul, Britannia and Hispania. But Constantine II wasn’t content with a third of the Roman Empire. He claimed as the firstborn son he should inherit the whole empire and invaded Italy in 340. Unlike his namesake, this Italian adventure did not go well, and he was killed shortly thereafter by Constans’ loyalists, which meant the young emperor now had two-thirds of the Roman world. In 341, after hearing about Constantine II’s death, Franks across the Rhine took advantage of the chaos and launched a series of raids, though Constans soon repelled them.
Constans successfully held his empire for another 9 years, though mismanagement and favoritism made him unpopular with the Rhine legions. In 350 the legions abandoned him and proclaimed Magnentius, a Roman general of probable Frankish descent, their new emperor. Constans fled south and made it as far as the Pyrenees before he was captured and executed. This coup d’état is a shocking example of just how much Gaul had changed. The fact that the legions would kill their Roman emperor and replace him with a Frank, shows just how powerful the Franks were and how they were accepted within the elite echelons of the military. Moreover, Britannia and Hispania immediately declared for Magnentius, meaning that with the exception of Constans himself, this was a virtually bloodless coup. In rapid order a Frank became master of the Western Roman Empire. As emperor he maintained the border and promoted Roman polytheism, against the encroachment of Christianity.
The eastern emperor Constantius II denounced Magnentius as a usurper and murderer of a rightful emperor. In response Magnentius marched east in 351 to conquer the central Roman Empire but he was defeated by loyalists to Constantius II, and had to retreat to Gaul. But while he was gone the Alemanni attacked under the pay of Constantius II, which further weakened the usurper’s grip on the Western Empire. In August 353 the two emperors met at Mons Selecus, today La Bâtie-Montsaléon, in the French Alps, where Magnentius was defeated and committed suicide by falling on his sword. This victory left Constantius II as the sole ruler of the Roman Empire. But for Gaul, the damage had been done. Constantius II had paid the Germans to raid, and if you know anything about Germans, you should know raiding is something that they were very good at. Franks, Alemanni and Saxons razed forty cities along the Rhine and carried off their inhabitants, few of which were ever seen again. Widespread devastation led to new bagaudae, impoverished starving peasants who formed raiding bands just to survive. Meanwhile, Constantius was attacked by Persia in the East and took the most elite troops with him.
As Rome abandoned Gaul, it was up to the Franks to defend it. Constantius II commissioned the Frankish-Roman Claudius Silvanus to defend Gaul from invasions across the Rhine. Silvanus was remarkably effective given his limited resources. He defeated those he could, bribed and compromised with others, and brought stability, if not peace, to Gaul in the next few years. If Silvanus expected a triumph for his victories he was sorely disappointed. Constantius II had been paranoid since childhood when much of his family was executed. In 355 some of his advisors convinced him that Silvanus was planning to establish himself as an emperor, even going so far as to alter a letter he sent using a sponge. While Silvanus was still guarding the west, Constantius II held a trial for a him. His two Frankish generals Mallobaudes and Malarich defended Silvanus, but the Roman faction outnumbered them and condemned him to death. Silvanus was in Mediolanum on his way to church when he was assassinated.
At this point most Roman Emperors preferred living in Constantinople presiding over the rich Eastern Empire, rather than the decaying West. But Constantius II knew he couldn’t abandon Gaul completely; if Gaul fell then Hispania and Italy itself would be open to more Germanic raids. While at Mediolanum he uplifted his cousin Julian to the role of Caesar. Julian showed natural talent as a military commander and over the next six years fought to reclaim the lost cities along the Rhine. He retook Colonia Agrippina, modern-day Cologne, in 356. He planned an invasion along northern Gaul in 357, but a rebellion of laeti Franks at Lugdunum forced him to turn around. The Franks had a lot to be angry about; they were still furious that Constantius II had murdered the popular leader Silvanus. Furthermore, Constantius sent a Roman official named Paulus to Gaul to root out Silvanus’ old supporters. Paulus had such a fierce reputation for torture that he acquired the name Catena or ‘the chain.’ Despite this, Julian and his loyal Franks subdued the rebellion.
After putting down the revolt Julian returned to the Rhine to rebuild the border fortresses. This angered the Alemanni king Chnodomar, who believed that Rome’s days of controlling the perpetual boundary dividing Germania from the ‘civilized’ world were over. In 357 Chnodomar marched to Argentoratum, modern-day Strasbourg, with an army tens of thousands strong, to meet Julian’s army, which may have been half the size, though as usual we have to take these estimates with a grain of salt. Chnodomar marched past the ruins of Argentoratum, confident they would never be rebuilt and stared down the Romans across a wide field.
The Germans assembled to meet the Roman army. The infantry made up the bulk of the forces, while reinforcements hid in the woods on his right flank. The German cavalry stood on the far-left, facing the Roman cavalry. Chnodomar knew his cavalry couldn’t match the Romans and instead hid infantry amongst the cavalry, who were ready to stab Roman horses with spears when they charged. At first this worked against the Germans as the Roman mounted cavalry fired on the German cavalry, who couldn’t maneuver due to the infantry interspersed among them. Then the Roman heavy cavalry charged and were decimated by the surprise German infantry. Now confident, the main German army let out a roar, charged across the field and crashed into the Roman formation. But as had happened so many times before, the Roman legions held their ground and devastated the Germans. The zealous Germans pushed the Roman center backward, but the army didn’t break. Instead, the further the Germans pushed the center forward the more the Roman flanks encircled them. Seeing their doom the German army broke and fled to the Rhine where many drowned or were cut down in the retreat. Chnodomar himself was captured and sent to Italy. This stunning victory inspired Julian to cross the Rhine and launch a series of punitive campaigns that lasted into 360. Multiple tribes became tributaries of Rome and he rebuilt numerous fortresses along the Rhine.
At this point, Julian’s star was rising. Gaul was the safest it had been since at least Constantine. Moreover he had won the respect of his Frankish allies. But in early 360 an envoy from Constantius II changed the course of history when he ordered Julian to send him his best soldiers for a campaign in Persia. The Franks knew that when Constantius II asked for the ‘best soldiers’ he meant them. The Franks were already furious with Constantius II for frequent abuses against them. They balked at the idea of marching across the world and abandoning their homes to potential German invasion. The Franks decided to take matters into their own hands and while they were stationed in Lutetia they proclaimed Julian an Augustus. Julian sent messages to Constantius II that this was done against his will but that now he couldn’t possibly refuse them or they’d kill him. The first part might have been a lie, as Julian was a highly ambitious leader who had proven his worth; perhaps he had spurred them to declare him emperor. But that last part, that the Franks would kill him if he didn’t do their bidding, was clearly true.
In 361, the furious Constantius II turned his armies around and marched towards Gaul to fight his upstart cousin. But fate was on Julian’s side: Constantius II fell deathly ill along the way. Realizing his time had come, and that Rome couldn’t survive another civil war, he ordered his armies and administrators to recognize Julian as the sole heir to the empire. But Julian struggled to manage the empire because of one small problem: he was a pagan. At this time most of the Eastern Empire, and a large portion of the West were Christian. Moreover, Christians provided vital charity and legal services which even non-Christians used. Julian tried to emulate the Christians by sponsoring pagan charities and encouraging pagans to act more virtuously. These efforts were unpopular and Julian knew he had to legitimize his rule, and what better way to accomplish this than through conquest? And what better place to conquer than Persia, that land of incredible wealth that would bring eternal glory to Rome…except every Roman who tried to conquer it died horribly? If only Julian listened to this podcast. But the ancient Romans did not have Apple Podcasts and in 363 he set off east alongside a number of Frankish generals and soldiers and died within a few months. When he did, the Frankish Roman general Flavius Merobaudes was given the honor of delivering Julian’s body to its final resting place in Tarsus.
In 364 Valentinian became the new Augustus of a collapsing empire. Germans used the chaos to overrun the Roman fortifications along the Rhine, while Goths crossed the Danube and the Persians engaged in the eternal tug-of-war with Rome in the East. Valentinian understood that he couldn’t rule the empire alone and he made his brother Valens Emperor of the East while he ruled in the West. Valentinian sped towards Lutetia to prepare a defense against an invasion by the Alemanni and for the next six years Valentinian repulsed the Germans. Initially it was a disaster as two Roman armies were repulsed. But then the tide turned and by 368 he engaged in punitive campaigns across the Rhine. Valentinian’s greatest asset was his use of diplomacy as he turned Germanic tribes against each other. Even the Alemannic king Macrianus, who was an enemy of Rome, became a loyal ally, largely because Valentinian offered numerous treaties that treated Germans as equals. Macrianus and the Alemanni allied against a conglomeration of Franks who threatened to overwhelm them both. But Macrianus’ loyalty was ill-rewarded. In 378 Valentinian’s successor Gratian allied with Mallobaudes, who was both a Frankish king and a comes or ‘noble’ within Roman Gaul. Their combined forces defeated the Alemanni and Macrianus was killed.
Just as Gaul was stabilizing, events in the east shattered the Roman world. Throughout the 4th century the Huns and Alans moved across the vast Asian steppe and into Eastern Europe. These incredibly-skilled nomadic warriors drove the Goths west and south until they spilled into Roman territory. On the 9th of August 378, the eastern emperor Valens ignored his Frankish general Flavius Richomeres and he and a large Roman army met a contingent of Gothic tribes and were slaughtered. This devastating blow opened up the Balkans to the Goths, and drove a wedge between the Western and Eastern Roman empires. After the battle Richomeres became the supreme commander of Eastern forces under the new emperor Theodosius I, but even he couldn’t hold the two halves of the empire together.
While the new eastern emperor Theodosius I fought to keep his half of Rome from falling apart, Gaul was relatively secure. But as we’ve seen so many times before in Roman history, just as things go well either a plague strikes or an emperor turns his people against him and everything falls apart. Gratian fell out of popularity in 383 and was supplanted by an upstart general Magnus Maximus, whose loyalists executed the emperor at Lugdunum. For four years Maximus maintained Britannia, Gaul, Hispania and Africa. But then he decided he wanted to add Italy to his domains and invaded. Maximus was defeated by Frankish general Flavius Bauto, who captured the upstart and executed him upon Theodosius’ orders in 388, while Richomeres’ nephew Arbogast strangled Maximus’ son at Trier.
Theodosius put his general Arbogast in charge of the West, where he ruled with absolute authority in practice, though he was officially just the regent for the young Valentinian II, who held court at Vienne. At this point the empire had two Romans at the head of government, Valentinian II in the west and Theodosius I in the east, but the armies were controlled by the Franks Arbogast and his uncle Richomeres. In retrospect this is a pretty shocking development, as the Franks, once considered one of Rome’s greatest enemies, now ruled over much of the empire. Richomeres was content to take his subordinate position as second-in-command to a Roman, though Arbogast and his cohort of Frankish generals were utterly contemptuous of the soft and foolish Romans. He put his lackies in positions of power at court, bullied Valentinian II into doing his bidding and at one point even killed one of Valentinian II’s friends as the young Roman watched helplessly.
Valentinian II rightly feared for his life and sent secret messages to Theodosius begging for help. Meanwhile in 391-2 Arbogast launched punitive campaigns across the Rhine, as his Franks fought non-Romanized Franks. The campaign was a disaster, as his armies got caught in swamps and dense forests. Valentinian II took advantage of Arbogast’s failure and dismissed him from service…but Arbogast simply ignored the order. When Valentinian II insisted that Arbogast had to step down, he Frankly had enough. On the 15th of May 392, Valentinian II was found hanged in his bedroom. Arbogast claimed he committed suicide, though no one was buying it. Arbogast decided to legitimize his authority by promoting a Roman, Eugenius, to the purple, to serve as a figurehead. By this point Christianity was popular even among the Gauls and the Franks, but there remained a sizeable population of polytheists. Eugenius tried to appeal to both and used public money to fund pagan ceremonies.
This usurpation and re-paganization of Gaul was too much for Theodosius I, who had officially declared Christianity the religion of the Roman Empire and banned pagan sacrifices. As hard-pressed as he was, in 393 he appointed his son Honorius to Augustus of the West and prepared for a conflict. Arbogast and Eugenius knew civil war was coming and tried to strike the first blow by invading Italy. This third invasion of Italy by a pretender from Gaul went as well as the last two, and both were killed by Theodosius’ armies.
In 393, Theodosius I elevated his sons Honorius and Arcadius to rule the West and East respectively. While we’re not going to follow events in the East much, it is worth noting that Arcadius’ wife was the daughter of Frankish general and former consul Bauto. Even though Franks weren’t emperors the fact that Romans were now marrying into Frankish noble families is one more piece of evidence showing just how powerful they were. Both of these emperors were figureheads who dealt with civil matters while generals managed their affairs. In the West, the Vandal general Stilicho, ran the empire. So far we haven’t spoken much about the Vandals because they were one of the smaller Germanic groups, though they are going to have a minor importance in Gaul in the early 400s.
While Honorius oversaw the Roman bureaucracy from Mediolanum, Stilicho crisscrossed the empire fighting Visigoths, Vandals, Alans and North African invaders. Stilicho was a brilliant and courageous general who repeatedly repulsed barbarian armies. But in order to do so he had to pull troops from the Rhine frontier until there were barely any troops left, which turned out to be a critical blunder. In December 406-7 parts of the Rhine froze over and numerous tribes of Vandals, Alans and Suebi crossed into Gaul. As they marched southwestward, Frankish soldiers protected their people and the Romans they lived beside and urged the incoming Germans to pass through. Most of these migrants went into Hispania, but they left behind chaos in Gaul. The common people saw that Rome was utterly impotent to defend its people and the veneer of Roman power was stripped away as everyone understood the Franks were the only reliable defense against invaders.
Chaos begat more chaos as a Roman general named Constantius, no relation to Constantine’s family, invaded Gaul from Britannia in 407. Constantius’ won some initial victories against the Germanic tribes, but spent most of his reign fighting Honorius. Stilicho lost a number of battles against Constantius’ forces and the Vandal general was executed in a political coup. None of his successors were up to the task of defending the empire. All of these pressures meant that in August 410 the Visigothic king Alaric I sacked Rome. This was the first time Rome had been sacked since around 390 BCE by the Gaul Brennus, roughly 800 years ago.
The sack of Rome caused outright panic across the empire. Even though the Eternal City was a shell of itself, it was still a symbol for the empire. If barbarians could sack Rome then nowhere was safe. To make things even worse, Constantius decided to invade Italy and make himself emperor of the Western Roman Empire. After so many usurpers from Gaul invaded Italy looking for glory, Constantius became the first successful- naw I’m just kidding, his forces were crushed and he was executed.
Even though Honorius and his generals defeated this usurper they still lost much of Roman Gaul. Armorica, the area we now call Brittany, did away with Roman rule and became an independent region. Northeastern Gaul belonged to the Franks while far-eastern Gaul belonged to the Alemanni. In 411 the Burgundian king Gundahar led his people across the Rhine and settled in eastern Gaul, in an area that stretched from modern-day Burgundy into western Switzerland. In 418 the Visigoths streamed into southwestern Gaul and created their own kingdom, with a capital at Tolosa, modern-day Toulouse. In response, the Romans moved the capital of Gaul from Trier, now controlled by the independent Franks, to Arelate in the south. Honorius later granted these peoples ‘permission’ to settle in Gaul, but it’s not like he had any choice and everyone knew it. After these invasions, Roman Gaul was a large chunk that included the middle-north, the middle and the southern coast, though it was poorly-defended and the central Roman authority was virtually non-existent. In 418 Honorius issued an Edict which removed imperial governors and granted near-full autonomy to the remaining Gallic territories. Roughly half of the former Roman province of Gaul was occupied by barbarians, the remaining half was autonomous and the Romans had no illusions about reconquest.
The 86 years between the death of Constantine and the death of Honorius showed how the Roman part of the Roman Empire had failed. The political system was a mess that led to frequent civil wars and public discord. The economy faltered and collapsed, even as the senatorial class maintained incredible wealth. But even though the Romans failed their empire the ‘barbarians’ were ready to pick up the slack, and among all the migrants to Rome, the Franks helped maintain the empire. The Franks may have been the majority of soldiers fighting along the Rhine in the late 4th century; they certainly made up a disproportionate number of the elite, who served across the Empire. I mentioned a fair number of generals but there are even more that I didn’t. One Frankish general named Merobaudes, a different Merobaudes than previously mentioned, served as the commander of Egypt in the 380s.
There is an ongoing historical narrative that Rome fell because of barbarian invasions and recurrent waves of migrants. Without question the vast numbers of migrants strained the Roman system, and the raiders and invaders did help topple Rome. But there’s another side to this story. Without the new groups of Romanized peoples that swelled the ranks of the army and military elite the empire certainly wouldn’t have made it as long as it did. It was the Romanized Franks and Stilicho the Vandal who held off their wilder cousins across the Rhine. It was the Frankish generals and Vandals who kept the empire together in the midst of Gothic invasions. Constantine brought throngs of Franks into Gaul in the belief that they would serve the empire and his gamble paid in dividends.
At least for a time. The Franks and other allies could not keep the empire together, especially as Roman leaders frequently betrayed, ignored or disrespected them. During the German mass migrations of 406-7 the people of Gaul depended on local Frankish lords and soldiers to protect them, as Rome had failed. Meanwhile as Rome declined and the Franks held their own lands they realized that they didn’t need Rome and probably would be better off without them. Thus, in the early 5th century the Franks didn’t revolt against Rome; they simply decided that they were done playing this game where they gave respect and honor to figurehead Romans and admitted the reality: Rome was decrepit and weak, while the Franks were vibrant and strong.
We’re nearing the end of the Roman Empire, though there are a few last topics to look at. We’ll look at how Gaul transformed into the divided realms of Francia, Burgundy, and the other kingdoms. But before Rome truly falls it will fight one last glorious battle against Atilla the Hun.
– The Franks by Edward James, 1988.
– The Roman Empire in Late Antiquity: A Political and Military History by Hugh Elton. 2018.
– Mary T. Boatwright, , Daniel J. Gargola,, and Richard J. A. Talbert, Romans: From Village to Empire 2004
– A History of the Later Roman Empire, AD 284-641: The Transformation of the Ancient World by Stephen Mitchell.
-A History of Gaul by Gregory of Tours