
Originally Posted by
NikosMaximilian
I'm sorry, but you are ignoring many factors outside the military field in your hypothetical scenario. Flavius Aetius won the Battle of Chalons by forging an alliance with Alaric, the King of the Goths. The alliance grew out of desperation: by that time the Western Roman Empire armies were nowhere near the legions of the past. A great percentage of the army was compossed by Germanic soldiers whose loyalty was divided between Roman gold and their own warchiefs. These troops weren't an organized army, they resembled more of a warband, so their discipline, organization and loyalty were inferior. The equipment was of poorer standards too: the Empire was in a bad financial situation, so there were less state provided shields and swords, and they were of worse quality.
Also don't forget that after the Catalaunian Plains, Attila didn't go away and invaded Italy. The only thing that stopped the Huns was the sudden death of their leader, who united several nomadic confederations.
I think that your claim that if he had proclaimed himself Emperor, he would have driven the Germanics out of the Empire provinces, is also wrong. The Empire was heavily dependant on foreign troops who sometimes responded to the Germanic warlord, sometimes to the Roman (promises of) gold and lands. There was no practical standing army, and the recruitment pool in the Western provinces had dwindled in the last hundred years, because of many factors (demographic crisis, climate change, loss of African grain, de-urbanization, invasions, etc.).
A realistic "what if" point for those who are interested in the survival of the Empire would the the Third Century Crisis, where the tide could have been changed. By the fifth century, there was no going back. Even if Aetius managed to beat migration after migration in the battlefield, the economic and social changes had sealed the Empire's destiny. In this scenario, my wild guess, is that it could have lasted a maximum of another 100-150 years but with its powers and territories greatly diminished. There are some other key moments that could have slowed down its fall like the reign of Constantine, Adrianople, the crossing of the Rhine, the first sack of Rome (its importance more about the message sent to the rest of the territories than the sack itself).
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