The Gallic Empire refers to a breakaway realm of the Roman Empire that only existed for about 14 years,from 260 to 274 CE. Throughout those years the Gallic Empire was wracked by a serious degree of infighting between rival generals. Although the first Gallic Emperor, Postumus, was able to fend off such challenges during the first half of its existence, his death and the succession of no less than 5 usurpers/emperors from 268-274, sealed it's fate.
Now to change the situation and let the Gallic Empire survive, you would need Postumus to survive. Easy way, and I don't know how accurate it is since I'm borrowing from Wikipedia, have his allow his soldiers to sack Mogontiacum. Apparently his refusal to allow this was what led to his death in 268.
The Gallic Empire refers to a breakaway realm of the Roman Empire that only existed for about 14 years,from 260 to 274 CE. Throughout those years the Gallic Empire was wracked by a serious degree of infighting between rival generals. Although the first Gallic Emperor, Postumus, was able to fend off such challenges during the first half of its existence, his death and the succession of no less than 5 usurpers/emperors from 268-274, sealed it's fate.
Now to change the situation and let the Gallic Empire survive, you would need Postumus to survive. Easy way, and I don't know how accurate it is since I'm borrowing from Wikipedia, have his allow his soldiers to sack Mogontiacum. Apparently his refusal to allow this was what led to his death in 268.
You also need to find a way to stop the Romans of Gaul wanting to, y'know, conquer Rome and the whole Empire. That's the difficult thing, IMO.