[kach22i]

Gallic Empire
https://en.wikipedia.org/wiki/Gallic_Empire

The Gallic Empire (Latin: Imperium Galliarum)[note 1] or the Gallic Roman Empire are names used in modern historiography for a breakaway part of the Roman Empire that functioned de facto as a separate state from 260 to 274.[note 2] It originated during the Crisis of the Third Century, when a series of Roman military leaders and aristocrats declared themselves emperors and took control of Gaul and adjacent provinces without attempting to conquer Italy or otherwise seize the central Roman administrative apparatus.[7]

It was established by Postumus in 260 in the wake of barbarian invasions and instability in Rome..............

Postumus
https://en.wikipedia.org/wiki/Postumus

Marcus Cassianius Latinius Postumus[3] was a Roman commander of Batavian origin who ruled as Emperor in the West. The Roman army in Gaul threw off its allegiance to Gallienus around the year 260,[note 1] and Postumus assumed the title and powers of Emperor in the provinces of Gaul, Germania, Britannia and Hispania, thereby founding what scholars have dubbed the Gallic Empire. He ruled for the better part of ten years[note 2] before he was murdered by his own troops...................

..................Although Postumus was able to capture Mogontiacum and kill Laelianus within a few months, he was unable to control his own troops, who wished to put Mogontiacum to the sack. When Postumus tried to restrain them, his men turned on him and killed him.[13][40]...........