The Usurpers Magnentius and Vetranio

About this time an extraordinary upheaval shook the whole state. We will give a brief account of its main points, since we think it necessary not to pass over them altogether. We mentioned in our first book that after the death of the founder of Constantinople his three sons succeeded him in the empire. It must now be added that a relative of theirs, Dalmatius, named after his father, shared the imperial power with them. He had been their partner in the sovereignty for only a very short time when the soldiers put him to death, Constantius neither ordering his death nor forbidding it. [a]

How Constantine the Younger was also killed by the soldiers, when he invaded the part of the empire that belonged to his brother, has already been told more than once. After his death the Persian war broke out against the Romans, and Constantius had no success in it: in a battle fought by night on the frontier between the two powers, the Persians had a slight advantage. This came at a time when the affairs of the Christians were no less unsettled, for there was great disturbance throughout the churches over Athanasius and the term homoousion.

When things had reached this point, a usurper named Magnentius rose up in the western parts. By treachery he killed Constans, the emperor of the western division of the empire, who was living in Gaul at the time. A furious civil war followed. Magnentius made himself master of all Italy, brought Africa and Libya under his power, and even took possession of Gaul. But at the city of Sirmium in Illyricum the army set up another usurper, named Vetranio, while a fresh trouble threw Rome itself into turmoil. For a nephew of Constantine, Nepotian by name, seized the sovereignty there with the backing of a band of gladiators. He was killed, however, by some of the officers of Magnentius, and Magnentius himself invaded the western provinces and spread devastation everywhere.