The Gallic Empire's Biggest Success to Rome

Previously the Gallic Empire's biggest success to it seems to be that it wasn't directly trying to challenge Rome for Imperial authority. The Eastern Empire, what happens in the East, is almost along the same lines of that, except it seems to have gotten more Imperial endorsement. We're on the scene here in the East now, after Valerian, one of the Petorian Prefects, and a large number of senators have been captured.