The story that ancient authors have given of Tetricus’ surrender at the Battle of Châlons has been questioned by some modern historians, who have reasoned that a surrender before the battle would have made more sense to avoid unnecessary carnage, that Tetricus was confident in his position and fought to the end, and that the story was just propaganda to help cement Aurelian’s rule.
We disagree with this view. The Gallic regime had seen three rulers assassinated in the past 5 years, a further two usurpers had appeared in the region in Tetricus’ time, there were economic problems emphasized by the sharp decline in the quality of Gallic coinage since c.268, the Germanic tribes continued to threaten across the Rhine, and Aurelian, after easily defeating the far more stable and successful Palmyrenes, was now mobilizing his entire army against them. It would not be surprising if the Gallic regime had by now split into pro-reconciliation and die-hard factions, explaining both why Tetricus could not have surrendered at the beginning of the battle (he would have been killed) and why much of his army continued to fight on after he surrendered. The surrender story also explains why Aurelian later rewarded Tetricus by making him governor of Lucania, Italy.
Sometime in 274 Faustinus, Tetricus’ governor of Belgica, went into revolt and proclaimed himself emperor in Augusta Treverorum (Trier). Records of this rebellion are vague, but as it broke out in Tetricus’ capital, it is possible that it occurred after Tetricus began marching south to face Aurelian, or even after Tetricus’ surrender. Either way, Faustinus was quickly crushed, by either Tetricus or Aurelian.in wikipedia
In the spring or early summer of 274 Aurelian marched against the usurper Tetricus in Gaul, meeting him on the Catalaunian Fields (near modern Châlons-sur-Marne). Tired of his mutinous officers and already in secret talks with Aurelian, Tetricus surrendered in mid-battle, but his troops fought on and were massacred. Victorious, Aurelian swiftly received the recognition of the provinces of Gaul and Britain, restoring central Roman rule in the West.in wikipedia