Editing 260 (section)

==== Roman Empire ====
* [[Battle of Edessa]]: With a large army, said to number 70,000 men, [[Valerian (emperor)|Valerian]] attempts to drive the Persians back from Edessa. The Roman army is surrounded and most of its troops are killed or captured. Valerian is taken prisoner for the remainder of his life.
* King [[Shapur I]] captures Valerian.<ref>{{cite journal | page=136 | title=The Coinage of Vabalathus and Zenobia from Antioch and Alexandria | first=Roger | last=Bland | url=https://www.jstor.org/stable/42667232 | access-date=February 9, 2024 | journal=The Numismatic Chronicle | volume=171 | year=2011| jstor=42667232 }}</ref>
* King Shapur I sends Valerian to [[Bishapur]] and uses the captured [[Roman army]] for engineering plans. They construct the ''[[Band-e Kaisar]]'' ("Bridge of Valerian").
* [[Gallienus]] becomes the sole emperor of [[Ancient Rome|Rome]]; during his reign the [[Pannonia]]n governor [[Ingenuus]] revolts on the [[Danube]].
* Gallienus evacuates the [[fortification]]s ([[Limes (Roman Empire)|limes]]) in the ''[[Agri Decumates]]'' ([[Germania Superior]]), covering the [[Black Forest]] area in the face of invading [[Alamanni]].              
* Gallienus establishes himself at [[Mediolanum]] (modern [[Milan]]); he reorganizes the army, supported by elite [[cavalry]], and dispatches troops to the [[Rhine]] frontier.
* [[Postumus]], Roman [[usurper]], forms the [[Gallic Empire]] and protects the Rhine against an invasion of [[Germanic peoples|Germanic tribes]].  
* [[Saloninus]], son of Gallienus, is proclaimed ''[[Augustus (title)|Augustus]]'' by his troops. Postumus besieges [[Cologne]], where [[Silvanus (praetorian prefect)|Silvanus]] is [[praetorian prefect]] and Roman ruler of [[Gaul]].
* Postumus executes Saloninus and his adviser Silvanus after breaching the walls of Cologne. He is recognized as emperor and establishes his capital at [[Trier]].
* Postumus wins over all the [[Roman province]]s west of the [[Alps]], including Gaul, [[Roman Britain|Britain]] and [[Hispania]].       
* The Roman [[castellum|fort]]  of [[Wiesbaden]] ([[Germany]]) is captured by the Alamanni.
* The [[Franks]] take control over the [[Scheldt]] estuary (approximate date).