What caused the fall of the (Western) Roman Empire?

Rome's advantage fell because Rome's enemies learned from the best. The tribal confederations of Caesar's day gave way to the proto-kingdoms of Valentinan's day. These kingdoms formed due to a combination of Roman subsidies to loyal leaders and Roman weapons trade.

One reason is that Germanic warfare shifted from the practice of a small elite to an increasingly large percentage of the male population, in no small part due to weaponry becoming cheaper to procure.

While there were reasonably coherent ethnic identities the 'barbarians' were really more of an army than a people, though many no doubt brought their wives and children.
 
Compared to the 2nd century, in the period of 275 up to Adrianapole, the Roman edge had eroded.

The above post hits the nail on the head pretty well. In absolute terms, the Roman army had almost total military supremacy right down to the 5th century. It was the rise in relative power on the part of the Sassanids, Germans, and eventually the steppe nomads, that forced the Roman military to increase in size and change its strategic disposition.
 
Caligula could have stood a chance had he been one of the Severii, Caracalla did for 6 years after all.

Nope, Caligula was far more insane. Caracalla was cruel, but not insane. Caligula would have lasted months on average during the Dominate era.

Someone like Claudius wouldn’t have gone for the purple in the first place in the third century.

So the stability of the Principate unlike the Dominate, allowed someone like Claudius to be a stable emperor?

Emperors wouldn’t be the first military commanders to be killed in a mutiny. Very often, soldiers in the third century had no intention of fighting for an emperor who would clearly lose against his contender, so they just dispatched him to save themselves. Maximinus was killed by his soldiers when his siege of Aquileia failed, Philip was killed either in battle or by his troops when facing Decius, Trebonianus was killed by his troops when facing Aemilianus, Aemilianus was killed by his troops when facing Valerian.

Soldiers do not kill their emperor in defiance of their sub-commanders, knowing they’d be harshly punished/executed afterwards.

The army made the empire stable, not the senators. As long as the army was well paid, well provided for and didn’t have to move too much from one corner of Europe to the other, the empire stayed stable.

I can’t believe anyone who knows anything about Roman history believes the ARMY is responsible for political stability. During the Dominate, every time the emperor lost a war, he was offed. Everytime he refused Praetorians another pay raise he was killed. The Army backed usurpers constantly so long as they were promised cash by them. They had ZERO loyalty to any central authority, and enabled/encouraged civil wars constantly.

Considering the empire began recovering after Gallienus, and managed to survive another two centuries, I’d say history is on Gallienus’ side. You can’t also expect things to stay the same over the centuries, it’d be like pretending that 19th century Europe was the same as 20th century Europe.

You are under the impression the Principate model failed, and the empire was resuscitated by the Dominate equestrian model. You should know as early as Severus, equestrians were replacing senators as governors and legionary commanders, the Senate lost authority even in Italy. It’s thus reasonable to say that Severus’ reforms led to future instability, not that the Principate model failed.

I said generally equestrians were better. There were good generals who were senators, they were the ones who bothered with staying in the army as tribune for more than a year. Few did that.

You’ve not addressed my point is that wars and military experience make good generals, not merely serving in the army in peacetime. Thus equestrians became better because they fought extended campaigns, during the Principate, senators fought extended campaigns and were superior.

It's also important to note that the equestrians vastly outnumbered the Senate which is why they produced more commanders, and thus high quality ones. There were plenty of useless equestrians, but due to their numbers they produced talented ones. Under the Principate, the talented Equestrians would be raised to the Senate, and the same benefit to the empire registered. Because they were novus homo however in the Senate, this discouraged ambition, and reduced chances of usurpation compared to if you eliminated the Senatorial class, and made the Equestrian class just one step from the emperorship.
 
Last edited:
The above post hits the nail on the head pretty well. In absolute terms, the Roman army had almost total military supremacy right down to the 5th century. It was the rise in relative power on the part of the Sassanids, Germans, and eventually the steppe nomads, that forced the Roman military to increase in size and change its strategic disposition.

The Romans did not have the SAME level of military supremacy pre-50 year crisis, and post-50 year crisis. As for relative power, I don't buy the later barbarian migrations were more of a threat to Rome compared to say the Marcomannic Wars. The only difference is largely the qualitative decline of the Roman army. (lower pay, conscription, worse fighting tactics, loss of engineering expertise, lower morale/fighting spirit) Admittedly, the Sassanids were far more formidable enemies as were the Huns, but that's about it.
 
Last edited:
The Romans did not have the SAME level of military supremacy pre-50 year crisis, and post-50 year crisis.

Well that's undeniable, I don't think anyone is debating that.

As for relative power, I don't buy the later barbarian migrations were more of a threat to Rome compared to say the Marcomannic Wars. The only difference is largely the qualitative decline of the Roman army. (lower pay, conscription, worse fighting tactics, loss of engineering expertise, lower morale/fighting spirit) Admittedly, the Sassanids were far more formidable enemies as were the Huns, but that's about it.

Can you cite specific examples? Because I have a hard time believing that the late Roman army was qualitatively worse than that of the principate. The Romans were able to decisively win both pitched battles and attritional campaigns as late as the reign of Constantius III, and even later during the civil war of Aetius and Bonifacius. The later Germanic migrations were likewise symptomatic of the Hunnic invasion, rather than necessarily being the decisive threat in their own right, in my opinion
 
Almost all historians would agree the Dominate never saw the same levels of trade and economic prosperity compared to the pre-50 year crisis. The late 3rd century army had notable victories AND notable defeats. In the Principate, Roman armies were almost always victorious. This was no longer the case. Defeating Persia/Parthia is not a major achievement compared to the Principate, when Roman armies were regularly sacking Ctesiphon. Romans only pushed the frontiers east in 300 CE, because emperors put more emphasis on the east through a division of power (East and West) and eventually, moving the capital to Constantinople.

Regularly? It mostly happened during the third century. It happened only once before then, under Trajan.



Yes they did. There were security problems in Britain. Parthia attacked. Severus had to campaign in Germania. Obviously these weren't terminal problems for the empire, but the same never happened in the Late Republic. No external enemies dared to attack Rome even when it was mired in decades of civil war.

Cimbri? Teutons? Also, the late republic’s borders were way less extended.



Due to conscription. Quality and morale had fallen by then compared to the Principate army. Soldiers received much lower pay for example. And they didn't have as much morale COMPARED to the Principate army.

Neither did, morale merely shifted away from Italy.
 

Justinianus

Banned
Also, the late republic’s borders were way less extended.
250px-Roman_Republic-44BC.png


The Roman Republic in 50 BC

images


Roman Empire in the 3rd Century

I dunno if that really matters all that much. While the Empire covered far more land than the Republic, the Empire's borders were also along much more defensible frontiers, the Rhine and Danube in Europe, Hadrian's Wall in Britain, Desert in North Africa and Levant, and Mountainous Armenia in Anatolia. And having all that territory also gave the Romans more resources towards their defense.

The reason why the Empire was at more risk in the 3rd century from external threat was because the external threats were far larger and organized in the 3rd century AD than in the Late Republic instead of anything wrong with the Roman State. Send the Empire of the 3rd Century back to the Late Republic era and they'd likely have a similar experience.
 
Nope, Caligula was far more insane. Caracalla was cruel, but not insane. Caligula would have lasted months on average during the Dominate era.

Don’t know how many of Caligula’s tales of insanity are actual truth or mere slander.



So the stability of the Principate unlike the Dominate, allowed someone like Claudius to be a stable emperor?

Or, different times require different emperors?



Soldiers do not kill their emperor in defiance of their sub-commanders, knowing they’d be harshly punished/executed afterwards.

Go tell that to Cinna, if not to the countless emperors who got killed by their troops. The rank and file are still human beings, and humans snap eventually.



I can’t believe anyone who knows anything about Roman history believes the ARMY is responsible for political stability. During the Dominate, every time the emperor lost a war, he was offed. Everytime he refused Praetorians another pay raise he was killed. The Army backed usurpers constantly so long as they were promised cash by them. They had ZERO loyalty to any central authority, and enabled/encouraged civil wars constantly.

The army was the backbone of the empire, all that it held it together. Once the Roman army stopped being Roman, the Roman Empire was no more.

Plus, what yoh’re describing is closer to the third century. Pretorians weren’t even around during the Dominate.



You are under the impression the Principate model failed, and the empire was resuscitated by the Dominate equestrian model. You should know as early as Severus, equestrians were replacing senators as governors and legionary commanders, the Senate lost authority even in Italy. It’s thus reasonable to say that Severus’ reforms led to future instability, not that the Principate model failed.

I’m not saying the Principate model failed, Times evolve, things change, and before Alexander Severus got killed, the army was loyal to a dynasty. It’s not really his fault his heirs weren’t on par with the model of emperor required for the times. Also, the power basically went back to the senators with Constantine, during the Dominate, which is the time that goes from Diocletian onwards, not from Septimius, that was still the Principate.



You’ve not addressed my point is that wars and military experience make good generals, not merely serving in the army in peacetime. Thus equestrians became better because they fought extended campaigns, during the Principate, senators fought extended campaigns and were superior.

After Tiberius, few hard campaigns were ever fought. Only Trajan, Corbulo and perhaps Agricola fought a genuinely hard campaign.

It's also important to note that the equestrians vastly outnumbered the Senate which is why they produced more commanders, and thus high quality ones. There were plenty of useless equestrians, but due to their numbers they produced talented ones. Under the Principate, the talented Equestrians would be raised to the Senate, and the same benefit to the empire registered. Because they were novus homo however in the Senate, this discouraged ambition, and reduced chances of usurpation compared to if you eliminated the Senatorial class, and made the Equestrian class just one step from the emperorship.

Or the usurpers would just be senators, as the two Gordians, Pupienus, Balbinus, Decius, Trebonianus, Aemilianus, Valerian and Gallienus. Also, the plural is novi homines.
 
Last edited:
250px-Roman_Republic-44BC.png


The Roman Republic in 50 BC

images


Roman Empire in the 3rd Century

I dunno if that really matters all that much. While the Empire covered far more land than the Republic, the Empire's borders were also along much more defensible frontiers, the Rhine and Danube in Europe, Hadrian's Wall in Britain, Desert in North Africa and Levant, and Mountainous Armenia in Anatolia. And having all that territory also gave the Romans more resources towards their defense.

The reason why the Empire was at more risk in the 3rd century from external threat was because the external threats were far larger and organized in the 3rd century AD than in the Late Republic instead of anything wrong with the Roman State. Send the Empire of the 3rd Century back to the Late Republic era and they'd likely have a similar experience.

Of course, more organized and persistent threats were a part of the crisis, however defending those natural borders was no easy task. Hadrian’s Wall could easily be scaled by a determined invasion force, Armenia wasn’t always in Roman hands, it was a constant object of contention between Persia and Rome, and th Danube was way too extended to station enough soldiers to properly defend it. The limes was always meant to discourage or handle small scale raids and regulate traffic in the border. The empire always had an offensive mindset. Emperors either sent punitive expedition to preempt invasion, or let the invasion pass through, only to smash it when on its way back.
 
Compared to the 2nd century, in the period of 275 up to Adrianapole, the Roman edge had eroded.

It was still adequate in any event.

I never said Roman equipment declined, only their fighting spirit, that's what I mean by qualitative edge. In the early Principate, Late Republic, Romans were more motivated by the barbarians. By the late 3rd century motivation for the two sides had closed.

Barbarians were certainly motivated at the time of the Varrian disaster of 9 CE.... Both sides seem equally motivated down to the 370s or so--the barbarians for plunder and territory, the Romans to defend their home--and at times, to advance their careers.
 
Almost all historians would agree the Dominate never saw the same levels of trade and economic prosperity compared to the pre-50 year crisis. The late 3rd century army had notable victories AND notable defeats. In the Principate, Roman armies were almost always victorious.

Trade fell off but prosperity may not have, to quite the same degree; Southern wrote about economic life "restructured on a local basis" and Heather wrote of continued prosperity down to c 400.
Roman armies suffered grave setbacks even in the principate--and even prior to the third century crisis. Besides the Varrian disaster, there was a setback fighting Dacia around the time of Domitian, an initial humiliation in the jewish war c 66, the loss of a legion in the Bar Kockba rebellion, the loss of another one c 161 in Armenia, the failure at Hatra in the time of Severus (and even Trajan a century earlier).

This was no longer the case. Defeating Persia/Parthia is not a major achievement compared to the Principate, when Roman armies were regularly sacking Ctesiphon. Romans only pushed the frontiers east in 300 CE, because emperors put more emphasis on the east through a division of power (East and West) and eventually, moving the capital to Constantinople.

They pushed the frontiers east because they were in a strong position following victory in 298 and the capture of the Persian king's wife and daughter.

Yes they did. There were security problems in Britain. Parthia attacked. Severus had to campaign in Germania. Obviously these weren't terminal problems for the empire, but the same never happened in the Late Republic. No external enemies dared to attack Rome even when it was mired in decades of civil war.

Well I don't know if the Teutones and Cimbri would concur with that. :) And btw that was within the last century of the republic long after Rome had risen to mastery of the Western world.
Generally the threat of barbarians was just less (usually) in the late republic and principate than in the third century. By the latter time the goths and franks posed a worse threat than previously. But the empire still coped down to about fifth century.

Due to conscription. Quality and morale had fallen by then compared to the Principate army. Soldiers received much lower pay for example. And they didn't have as much morale COMPARED to the Principate army.

Morale or at least willingness to serve and fight had to have been good. There was mandatory service in the fourth century too, for example sons of soldiers had to serve, but that didn't ultimately work out.
 
Adrianople was entirely avoidable, Goths couldn’t be kept under control because after the battle they’d already got in, and Theodosius couldn’t get them out and chose to just settle them.

They had to tolerate the goths and try to secure their cooperation because they just lacked the strength to evict them or get them under control. This was symptomatic of growing military weakness at the time.


I read his biography by John White, and he doesn’t mention Goths attempting to settle in.

I read White and he does.

Never said he was. He was terrible actually, but his soldiers didn’t know that yet, but you’re right, I mixed up the dates. In any case, the arguments still valid, Gallus proved an unworthy general after a serious defeat, thus he was overthrown.

Lol Gallus was not a general during his reign 251-53. He was overthrown because a victorious general was elevated by his troops.

Because for the first time there were two emperors around, not one, and they were both capable generals. Gallienus repelled more than one barbarian invasion even before 260.

He certainly faced deep barbarian raids...dunno if he fought effectively on his own, since his old man had to come back west to him c 257-8.

They weren’t happy about him dying, that doesn’t mean they’d just forget how to fight altogether. Gallienus had been their commander for 18 hard years, more than any other emperor during the crisis, it’d be weird if they didn’t feel attached.

He was in authority for 15 years but he must've had issues with many troops since usurpers started acting up immediately after Valerian was gone. Ingenuus, Regalianus and later even Aureolus (sp?)



At least according to Ian Hughes and his map on the event, they were briefly stopped at the end of 429 by an emissary could Darius, then they went back on marching until they reached Hippo in Summer 430 and the siege began. There was an incursion in Numidia, never denied it, but not in Proconsularis.

According to Jacobsen's map the Vandals already reached Carthago around the start of 430 but failed to take it in a surprise move, so they just split into two main groups to loot the surrounding areas.
 
The Romans did not have the SAME level of military supremacy pre-50 year crisis, and post-50 year crisis.

I have doubts. Aurelian's army and Galerius's army fought better in the east than those of, say, Macrinus or Alexander Severus.


As for relative power, I don't buy the later barbarian migrations were more of a threat to Rome compared to say the Marcomannic Wars. The only difference is largely the qualitative decline of the Roman army. (lower pay, conscription, worse fighting tactics, loss of engineering expertise, lower morale/fighting spirit)

I don't think the Roman army declined in the sense of becoming qualitatively much inferior by c 350--400. Julian's army was tactically proficient. The main problem was unwillingness to serve on the part of most citizens so Stilicho needed barbarians.
 
They had to tolerate the goths and try to secure their cooperation because they just lacked the strength to evict them or get them under control. This was symptomatic of growing military weakness at the time.

Yes, but before Adrianople the empire could still control them, somewhat.








Lol Gallus was not a general during his reign 251-53. He was overthrown because a victorious general was elevated by his troops.

And it happened right after the heavy loss in the East. Doesn’t matter that he didn’t personally lose, in the third century only winning emperors could hope to not be overthrown.



He certainly faced deep barbarian raids...dunno if he fought effectively on his own, since his old man had to come back west to him c 257-8.

If the battle of Mediolanum is anything to go by, he wasn’t bad at all. Several inscriptions in Gaul also testify of his victories before 260.



He was in authority for 15 years but he must've had issues with many troops since usurpers started acting up immediately after Valerian was gone. Ingenuus, Regalianus and later even Aureolus (sp?)

Yeah, and none of them got him. His problem wasn’t with the troops, it was with his officers.





According to Jacobsen's map the Vandals already reached Carthago around the start of 430 but failed to take it in a surprise move, so they just split into two main groups to loot the surrounding areas.

I’m going to admit my ignorance and say that I had never heard of the guy before.
 
I have doubts. Aurelian's army and Galerius's army fought better in the east than those of, say, Macrinus or Alexander Severus.

Maybe, maybe not - but how do we measure that one army fought better than another one? Casualties (of their opponent) per thousand?
 
Maybe, maybe not - but how do we measure that one army fought better than another one? Casualties (of their opponent) per thousand?

Success or not I guess. One could argue that the troops weren’t exactly well led in the previous campaigns, but the Sassanids clearly employed a kind of warfare the Romans weren’t used to yet.
 
Maybe, maybe not - but how do we measure that one army fought better than another one? Casualties (of their opponent) per thousand?


Hi Max, We don't always--if usually-- have reliable stats. I suggest an army is more effective if it achieves its objectives against a foe of about the same capability.
 
And it happened right after the heavy loss in the East. Doesn’t matter that he didn’t personally lose, in the third century only winning emperors could hope to not be overthrown.

I don't think it happened right after the defeat in the east which occurred 252 whereas Gallus was ousted in 253--right after a victorious general of is was raised to the purple by his men.
 
Top