Backed by the provincial troops under his command, Marcus Cassianius Latinius Postumus laid claim to Gaul, Germania, Britannia and Hispania, becoming the first of the Gallic Emperors. This usurpation, complete with its establishment of parallel institutions of imperial government, went unchallenged by Rome for a few years, and when Gallienus himself finally led loyal legions north to dislodge Postumus, he failed in the attempt. Following this abortive campaign, Gallienus was compelled to turn his attention to a myriad of problems elsewhere, leaving Postumus free to resume his charade. That said, Postumus continued to effectively negate the barbarian threats along the frontier defined by the Rhine, and overall brought peace and prosperity,to the areas under his control.
After a decade of rule, Postumus successfully fended off a revolt by Laelianus, his governor in Germania Superior, but soon thereafter was nevertheless murdered by his own soldiers for having forbidden them from looting in the aftermath.
In the beginning, the precious metal coinage of Postumus actually was at least as competently rendered as and often of higher purity than the "official" issues of Gallienus, but as time passed significant.debasement took place.
The issue pictured below exhibits a well centered strike on a pretty round flan. Identified as RIC 75 (RSC 199, Sear 10962), probably struck at Cologne.

