After all, medieval society is generally seen as developing from a mix of Roman culture, Germanic culture, and Christianity, so we might as well embrace the centuries where those got all mixed together.
One of the major figures in Late Antiquity was Alaric the Goth. The Goths were a Germanic people who had lived at the eastern edges of the Roman Empire and had been wandering in during the fourth century. The Romans had recruited a number of their young men into their armies. The Goths were not an organized "tribe" but rather a large group of people who shared a lot of language and culture. There were two main subgroups, the Visigoths (meaning western Goths) and Ostrogoths (meaning, as you probably already guessed, eastern Goths.) In the late fourth century, the Visigoths lived in the Balkans.
(And no, the Goths did not wear heavy eye makeup and black fingernail polish. They also had nothing to do with Gothic architecture. One word, many meanings.)
And here we meet Alaric of the Visigoths (c. 375-411). He was recruited into the Roman army as a young man and helped the Romans defeat the Franks, another Germanic tribe (which eventually settled in the Empire, in what is now called France for them, but that's another story). He did not receive the accolades and rewards he felt he had been promised and left the army. But he gained a high position nonetheless in becoming king of the Visigoths in 395. (Guess Rome was showed!) (You note he's still only about twenty. This is a world of young men.)
The above is a nineteenth-century German picture of what Alaric might have looked like. Because he was Germanic, the nineteenth-century Germans liked him, as they tried to assemble a national identity.
He and his people were recognized by Rome but not given much respect. A recent author has tried to draw parallels between the Goths being treated as second-class by Italians, and modern African-Americans being discriminated against by mainstream American culture, but I think he's overdoing it (though I'm glad he's concerned about modern African-Americans). The leaders of the Roman Empire treated everybody like that. They were a slave society. Anyone who wasn't them was considered a lower being.
So I wouldn't call Alaric's concern a desire for his civil rights. After all, he spent most of his years as king plundering Roman territory. He had seen how wealthy the Romans were, and he went from plundering Greece to plundering Italy. It's an incredibly complicated story, involving rival emperors, imperial usurpers, treaties made and broken, ransoms promised and reneged on. It puts Game of Thrones to shame. It didn't help the Romans in the long run that they captured and killed a lot of the wives and children of the Goths during some of the wars' twists and turns.
In 410 Alaric and his Goths decided to sack the city of Rome itself. This was as you can imagine a shock to the citizens of Rome. The city had not been effectively attacked for half a millennium. But the Goths came through and seized everything that wasn't nailed down. One of the prizes Alaric took with him was the emperor's sister (who eventually married Alaric's brother, but that's another story.)
Above is a nineteenth-century French depiction of the sack of Rome. Visigoths are preparing to topple a Roman statue. It's unclear why they've decided to do so in the nude.
Now this was not the "fall of Rome." Several years later the city had rebuilt so successfully that Romans boasted you could hardly tell anything had happened. There continued to be, at least intermittently, Roman emperors in Rome, as well as the main emperors in Constantinople, for several more generations.
Alaric himself did not survive a year after the sack of Rome, dying probably of a fever. The story is that a stream was diverted from its course, and he was buried in the stream bed with suitable amounts of loot, and then the stream was allowed back into its banks, to conceal his final resting spot. To be sure, the slaves who had done the digging were all executed.
But the Visigoths, carrying lots of excellent loot, headed west, eventually settling in southern France and the Spanish peninsula, which was also part of the Roman Empire. They had picked up a variant of Christianity, Arianism (officially a heresy, it denies the divinity of Christ, calling Jesus just an inspired teacher). There they ruled until the rise of Islam two centuries later.
© C. Dale Brittain 2020
For more on medieval social and political history, see my book, Positively Medieval: Life and Society in the Middle Ages, available on Amazon and other e-tailers, either as an ebook or in print.