Europe 355: Silvanus
To stabilize Gaul, Constantius II sent the general Silvanus there, but, after being falsely accused of plotting to gain power, Silvanus felt forced to proclaim himself emperor in 355. The revolt lasted less than a month before agents of Constantius assassinated the usurper.
353–358 Shapur II’s Chionite War▲
In 353 Shah Shapur II was forced to travel to Margiana (Merv), on the northeast frontier, to fight off an invasion of the Sasanian Persian Empire by the Chionite Huns and their Kushano-Sasanian dependents. This war raged on for five years, during which Shapur wintered and minted coins at Margiana, until peace was established in 358. After this, the Chionites became Persian vassals and served with them as allies in the war against Rome.
??–Sep 353 Nohodares▲
While Persian Shah Shapur II was fighting the Chionites on his northeastern frontier, he left the prince Nohodares in command in Mesopotamia, with instructions to exploit any opportunity to attack the Romans. In 353 Nohodares led a daring expedition across deserts, up the Abora (Khabur) river, and deep into Roman territory in an attempt to strike at the wealthy town of Batnae (Suruç) during its September markets. The raid collapsed when some of his men defected to the Romans and revealed his plans; after which he returned to Persian territory and mounted no more invasion attempts.
354–355 Constantius II’s Alemannic War▲
In 354 Constantius II led his army to Augusta Raurica and, after an inconclusive battle over the Rhine, made peace with a tribe of Alemanni led by the brothers Gundomar and Vadomar. The following year Constantius marched against another tribe of Alemanni who were causing trouble around Lentia (Linz). Despite having an expeditionary ambushed on the shores of Lake Brigantia (Lake Constance), the Romans routed their enemy in a second encounter and imposed peace on that front too.
Oct 354 End of Constantius Gallus▲
In early 354 Constantius II sent his prefect Domitianus to investigate reports of tyranny by Caesar Constantius Gallus in the East, but when Domitianus arrived in Antioch his insulting behavior towards Gallus soon led to the prefect’s death. In a feigned attempt at reconciliation, Constantius then summoned Gallus and his wife, Constantius’ sister Constantina, to Italy, but the latter died of fever en route. Gallus was then arrested, stripped of his rank of Caesar, and taken to Istria, where he was beheaded.
11 Aug–7 Sep 355 Silvanus▲
In 355 Constantius II dispatched Silvanus—a Roman general of Frankish descent serving as magister peditum—to Colonia Agrippina (Cologne) to deal with Frankish raids on Gaul, but, soon after Silvanus left, letters appeared implicating him in a plot to seize power. Although the letters were soon proved to be forgeries, by this time Silvanus, learning of the investigation and believing he had no other options, had proclaimed himself emperor. Now facing a real usurpation, Constantius sent the magister equitum Ursicinus to deal with the situation. First winning Silvanus’ trust by pretending that he was defecting, Ursicinus quickly ended the reluctant rebel’s reign by bribing a number of soldiers to assassinate him.