The battle was over, and the usurper was captured. Now within the custody of Marcellus, Constantine found himself well guarded and protected. He was a valuable prize, one that Marcellus planned to march through the streets of Ravenna, much like how Aurelian had done to the Queen Zenobia after he had defeated her, and her breakaway empire.
As for the control of Gaul and Britannia, Marcellus immediately dispatched four legions to secure the regions. With Constantine's forces annihilated, a few garrisons would mostly protect the area. Leaving them open to Germanic conquest, something that Marcellus did not plan to let happen.