In the year of our Lord 377, Gratian, fortieth in line from Augustus, ruled as Emperor for six years from the death of Valens; he had already reigned as co-Emperor with his uncle Valens and his brother Valentinian. Finding the affairs of the State in grave disorder and approaching disaster, he chose the Spaniard Theodosius to restore the Empire in its need, investing him with the royal purple at Sirmium, and creating him Emperor of Thrace and the East.
At this juncture, however, Maximus, an able and energetic man, well fitted to be Emperor had not ambition led him to break his oath of allegiance, was elected Emperor by the army in Britain almost against his will, and he crossed into Gaul at its head. Here he treacherously killed the Emperor Gratian who had been dumbfounded at his sudden attack, and was attempting to escape into Italy. His brother the Emperor Valentinian was driven out of Italy, and took refuge in the east, where Theodosius received him with fatherly affection. Within a short time, however, he regained the Empire, and trapping the despot Maximus in Aquileia, he captured him and put him to death.