This sounds like the beginning of "Gladiator"
Hmmm, if you look at the Wikipedia, Maximus Thrax, the first of the soldier emperors (alledgedly 2,60 meters tall and able to drink a barrel of wine a day!) fought the "alemanni", which is generally interpreted to mean he fought somewhere in southern germany.
But perhaps the romans weren't too accurate which german tribe they were fighting or perhaps the alemanni in the third century were farther north than where they later settled and became a tribe of petty burgouis that invented the automobile (
).
Apparently Maximus Thrax gaving himself the "germanicus" title, and him being a soldier I suppose that this means he actually won a few battles there.
Problem is sources:
We don't have the abundance of written sources for the 3rd century like we do have for the 1st centuries BC and AD.
In the first century BC we often what happened every day in urban rome thanks to Cicero's letters and other classical writers.
For later times, written sources are a lot less prolific, especially about politics.
There's a lot of scientific work (grammar, philosophy, law) from that period, but hardly anything political or historical.