Galerius naturally could not stand idly by and see the very heart of the Empire wrested from his grasp, even though the new conquerors insisted they were loyal to him as Senior Augustus. Gathering an army, he marched from Nicomedia into Italy, only to find town after town fortified and garrisoned so strongly that, had he stopped to conquer them, his forces would have been exhausted before reaching Rome.
Once again Maximian and Maxentius poured out Roman gold to buy off the Illyrian legions who followed Galerius. And since the Emperor of the East was generally hated because of an edict decreeing a census of persons and property and payment of taxes in the area, he shortly found himself in the same position Severus had been in hostile territory with fortified strongposts at his back and a steady rate of defection in his own ranks. Remembering his experience during the hasty dash into Persia, Galerius chose the wiser course of retreat and, fuming but impotent, returned to Nicomedia, leaving Maximian and Maxentius in clear possession of the field.
Imperial ambassador
While Galerius was still in northern Italy, the wily Maximian made a third move, designed to insure that he and Maxentius would be free to advance eastward whenever they chose. A letter, couched in flowery terms and borne by an imperial ambassador, was delivered at Treves, inviting Constantine to meet the father of his beloved at Arles on the southern coast of Gaul, not far from Massilia. The avowed purposes of the meeting were twofold: first to invest the Caesar of Britain, Gaul and Spain with his rightful title of Augustus, and second to celebrate the wedding of Fausta and Constantine.
Constantine was natually overjoyed with the news from Rome and at once dispatched a courier with a message of acceptance and a magnificent necklace of emeralds he had purchased in Spain for Fausta. These pleasant duties finished, he went to the apartment of the Empress Theodora to notify her of his coming alliance with her family.
He found the Empress talking to an oliveskinned man whose features had a Spanish cast and whose dark eyes were bright with intelligence. He reminded Constantine somewhat of Eusebius of Caesarea perhaps because, like Eusebius, he wore the robe of a priest, though without the headgear of a cleric of high rank. Theodora came to greet Constantine, her hands outstretched in greeting, her eyes bright with welcome.
“We have seen too little of you in Treves, Augustus,” she said. “The children were asking about you today; your stepbrothers and stepsisters are very fond of you.”
Read More about Eusebius of Caesarea