Editing Constantius II (section)

===Further crises===
On 11 August 355, the ''[[magister militum]]'' [[Claudius Silvanus]] revolted in Gaul. Silvanus had surrendered to Constantius after the [[Battle of Mursa Major]]. Constantius had made him ''magister militum'' in 353 with the purpose of blocking the German threats, a feat that Silvanus achieved by bribing the German tribes with the money he had collected. A plot organized by members of Constantius's court led the emperor to recall Silvanus. After Silvanus revolted, he received a letter from Constantius recalling him to Milan, but which made no reference to the revolt. [[Ursicinus (magister equitum)|Ursicinus]], who was meant to replace Silvanus, bribed some troops, and Silvanus was killed.{{citation needed|date=September 2022}}

Constantius realised that too many threats still faced the Empire, however, and he could not possibly handle all of them by himself. So on 6 November 355,<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XV.8.17</ref> he elevated his last remaining male relative, [[Julian the Apostate|Julian]], to the rank of ''caesar''.<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XV.8.5–16</ref> A few days later, Julian was married to [[Helena, wife of Julian|Helena]], the last surviving sister of Constantius.<ref name="autogenerated2">[[Ammianus Marcellinus]], ''Res Gestae'' XV.8.18</ref> Constantius soon sent Julian off to Gaul.<ref name="autogenerated2"/>
[[File:2009 Carnuntum Heidentor1.jpg|thumb|Triumphal arch of Constantius II in [[Carnuntum]], Pannonia]]
Constantius spent the next few years overseeing affairs in the western part of the empire primarily from his base at Mediolanum. In April–May 357 he visited [[Rome]] for the only time in his life. The same year, he forced [[Sarmatians|Sarmatian]] and [[Quadi]] invaders out of Pannonia and [[Moesia|Moesia Inferior]], then led a successful counter-attack across the Danube.<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XVI.12</ref>

In the winter of 357–58, Constantius received ambassadors from [[Shapur II]] who demanded that Rome restore the lands surrendered by [[Narseh]].<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XVII.5.3–8</ref><ref>[[Joannes Zonaras|Zonaras]], ''Extracts of History'' XII.9.25–27</ref> Despite rejecting these terms,<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XVII.5.9–14</ref><ref>[[Joannes Zonaras|Zonaras]], ''Extracts of History'' XII.9.28–29</ref> Constantius tried to avert war with the [[Sassanid Empire]] by sending two embassies to Shapur II.<ref>[[Libanius]], ''Epistle'' 331</ref><ref>[[Ammianus Marcellinus]], ''Res Gestae'' XVII.14.1–3 & XVIII.6.17–18</ref><ref>[[Eunapius]], ''Lives of the Sophists'' VI. 5.1–10</ref> Shapur II nevertheless launched another invasion of Roman Mesopotamia. In 360, when news reached Constantius that Shapur II had destroyed [[Singara]] ([[Sinjar]]),<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XX.6</ref> and taken [[Hasankeyf|Kiphas]] ([[Hasankeyf]]), Amida (Diyarbakır),<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XIX</ref> and Ad Tigris ([[Cizre]]),<ref>[[Ammianus Marcellinus]], ''Res Gestae'' XX.7.1–16</ref> he decided to travel east to face the re-emergent threat.