Actually it was the exact opposite. Belgae were in a furious fight with other gallic tribes around the start date of our mod, pushing their way into central Gaul, coming from Germany. Eventually, they were stopped by the Aeduii, and settled into modern day Belgica.
Some time ago a large battle site was discovered in northern France or southern Belgica, with bones and armour pertaining our timeframe, and one perhaps may assume that it was one of the battles of this conflict.
My memory is a bit foggy though, and I might be horribly wrong.
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