From Constantine to Julian: [John the Monk], Artemii passio (The Ordeal of Artemius, BHG 170–71c, CPG 8082)

The feared civil war between the brothers Constantius and Constans was duly averted by the restoration of the exiled bishops. But in 350 Constantius found himself embroiled in a civil war against the Western armies because of the murder of his brother by agents of Flavius Magnus Magnentius, the comes of the Joviani and the Herculiani. He had declared himself emperor on 18 January at Autun and the rebellion found support from commanders who had grown tired of the excesses of an emperor who in later years had, in spite of his arthritis, become indulgent in hunting and the pleasures provided by young ‘barbarian’ boys (Zos. II, 42, 2-5 and Zon. XIII, 6, 1-12). To forestall another rebellion, Constantia, the sister of Constantius, persuaded Vetranio, the elderly magister peditum in Illyricum, to declare himself emperor on 1 March (Philost., H. e. III, 22 and Cons. Const., s. a. 350). Constantius who was then in Edessa on the Eastern frontier recognised Vetranio as emperor and placed him in command of the imperial troops on the Danube (Jul., Or. I, 30B). Vetranio’s example was quickly followed by Julius Nepotianus, the son of Constantius’ half-sister Eutropia, who declared himself emperor in Rome on 3 June 350; but he was subdued within a month by the forces of Magnentius who had gained controlled of Italy (Zos. II, 43, 2). Despite the threat of a renewed Persian invasion, Constantius

marched west with his main army to face the two usurpers who were now allied to each other. After much negotiation, Constantius managed to detach Vetranio from the alliance and persuaded the troops to strip him of the title of Augustus (25 Dec. 350). (Cf. Jul., Or. I, 27C, Pet. Patric., frag. 16, FHG iv, p. 190, Zos. II, 44, 3-4 and Zon. XIII, 7, 18-20.) Magnentius, who had by now secured Africa, declared his brother Decentius as Caesar to protect Gaul. Severe weather conditions now prevented Constantius from crossing over the Alps for the final contest with Magnentius and, worried by news he received of Shapur II’s plans to renew the offensive after the unsuccessful third siege of Nisibis in the summer, Constantius saw no option but to follow the example of Magnentius in appointing a Caesar to take charge of affairs in the East. As loyalty to the House of Constantine was now at stake, he proclaimed Gallus the elder of his two only surviving male cousins as Caesar on 1 March 351 and placed him in charge of the East. Constantius also sent his longserving prefect Philippus as envoy to Magnentius to seek peace but really to spy out his movements and strengths. In a rousing speech, he nearly succeeded in winning over Magnentius’ troops back to Constantius. A furious Magnentius refused to return him to Constantius on the grounds that he had abused his powers as envoy and kept him in custody in which situation he probably remained till his death (Zos. II, 46, 2-47, 3). (Cf. Jones, 1955:232.) After initial skirmishes at Ardana, a major battle between the forces of Constantius and Magnentius was fought at Mursa. It was a pyrrhic victory for Constantius and his defeated rival withdrew to Aquilea. The war continued in 352 as Constantius’ forces worked their way through northern Italy and across the Alps in the next year. A battle at Mons Seleucus in the summer of 353 finally sealed the fate of the rebellion. Magnentius committed suicide at Lyon on 10 August 353.