Europe 356: Julian’s Gallic Wars
Almost immediately after Silvanus’ death the Rhine frontier collapsed and Germanic tribes poured into Gaul, prompting Constantius II to appoint Julian, his sole surviving male relative, as Caesar in November 355 and dispatch him to the region. By the time he arrived, however, the important city of Colonia Agrippina (Cologne) had fallen to the Franks and the Alemanni were raiding as far as Augustodunum (Autun).
??–Nov 355 Siege of Colonia Agrippina▲
In late 355, shortly after the assassination of Silvanus, the Franks crossed the Rhine into Gaul and besieged Colonia Agrippina (Cologne), Silvanus’ former capital. After a lengthy siege, the great city fell to the invaders and was reduced to ruins in the sack that followed. Learning of this catastrophe by early December, Constantius II deliberately concealed it from his Caesar Julian until the latter was en route to Gaul, apparently afraid that he would decline his new post.
6 Nov 355 Julian Caesar▲
Learning of the Germanic invasions of Gaul, Constantius II appointed Julian—his cousin and last surviving male relative—as Caesar in Mediolanum (Milan) on 6 November 355. Barely twenty-three, and until this point a scholar of philosophy, Julian was married to Constantius’ sister Helena a few days later and on 1 December he was dispatched, with the advisors Marcellus and Sallustius, across the Alps to Gaul. Arriving in Vienne some weeks later, he settled down for winter and prepared for the next year’s campaign.
? ??–24 Jun 356 Siege of Autun▲
In late 355 or early 356 the Alemanni poured into Gaul and conquered many cities. By spring 356 a force of them had surrounded Augustodunum (Autun), whose great walls had fallen into a state of disrepair. Learning of the plight of this city, Julian led his army out from Vienne and quickly dispersed the besiegers.