3-3. The Deaths of Constantine II and Constans
Turning to the history of the West after the meeting of the Augusti in 338, it would appear, on the basis of his coinage, that Constantine forthwith claimed an authority superior to that of his co-rulers; he even legislated for Africa although this province fell within the jurisdiction of Constans. The latter, however, soon asserted his complete independence of his elder brother and in autumn 338 after a victory on the Danube assumed the title of Sarmaticus. At this time, he probably sought to enlist the support of Constantius, surrendering to the latter Thrace and Constantinople. Disappointed of his hopes, it would seem that the ruler of the West now demanded for himself both Italy and Africa. Early in 340 he suddenly crossed the Alps and at Aquileia rashly engaged the advanced guard of Constans who had marched from Naissus in Dacia, where news had reached him of his brother's attack.
Constantine, falling into an ambush, perished, and Constans was now master of Britain, Spain, and the Gauls. He proved himself a terror to the barbarians and a general of untiring energy who travelled incessantly, making light of extremes of heat and cold In 341 and 342 he drove back an inroad of the Franks and compelled that restless tribe "for whom inaction was a confession of weakness" to conclude a peace: he disregarded the perils of the English Channel in winter, and in January 343 crossed from Boulogne to Britain, perhaps to repel the Picts and Scots. His rule is admitted to have been at the outset vigorous and just, but the promise of his early years was not maintained: his exactions grew more intolerable, his private vices more shameless, while his favourites were allowed to violate the laws with impunity.
It would seem, however, to have been his unconcealed contempt for the army which caused his fall. A party at court conspired with Marcellinus, Count of the sacred largesses, and Magnentius, commander of the picked corps of Joviani and Herculeani, to secure his overthrow. Despite his Roman name, Magnentius was a barbarian: his father had been a slave and subsequently a freedman in the service of Constantine. While at Augustodunum, during the absence of the Emperor on a hunting expedition, Marcellinus on the pretext of a banquet in honour of his son's birthday feasted the military leaders (18 January 350); wine had flowed freely and the night was already far advanced, when Magnentius suddenly appeared among the revellers, clad in the purple. He was straightway acclaimed Augustus: the rumour spread: folk from the country-side poured into the city: Illyrian horsemen who had been drafted into the Gallic regiments joined their comrades, while the officers hardly knowing what was afoot were carried by the tide of popular enthusiasm into the usurper's camp. Constans fled for Spain and at the foot of the Pyrenees by the small frontier fortress of Helene was murdered by Gaiso, the barbarian emissary of Magnentius.
The news of his brother's death reached Constantius when the winter was almost over, but true to his principle never to sacrifice the Empire to his own personal advantage he remained in the East, providing for its safety during his absence and appointing Lucillianus to be commander-in-chief.
The hardships and oppression which the provinces had suffered under Constans were turned by Magnentius to good account. A month after his usurpation Italy had joined him and Africa was not slow to follow. The army of Illyricum was wavering in its fidelity when, upon the advice of Constantia sister of Constantius, Vetranio, magister peditum of the forces on the Danube, allowed himself to be acclaimed Emperor (1 March, at Mursa or Sirmium) and immediately appealed for help to Constantius. The latter recognised the usurper, sent Vetranio a diadem and gave orders that he should be supported by the troops on the Pannonian frontier. Meanwhile in Rome, the elect of the mob, Flavius Popilius Nepotianus, cousin of Constantius, enjoyed a brief and bloody reign of some 28 days until, through the treachery of a senator, he fell into the hands of the soldiers of Magnentius, led by Marcellinus the newly appointed magister officiorum.
To obtain a deluxe leatherbound edition of THE CAMBRIDGE HISTORY OF THE BYZANTINE EMPIRE, subscribe to Castalia History.