260 AD., Postumus, Colonia mint, Antoninianus, Elmer 131.

Postumus, Colonia (Cologne) mint, emission 4, 260 AD.,
Antoninianus (21-23 mm / 3,09 g),
Obv.: IMP C POSTVMVS•P•F•AVG, radiate, draped and cuirassed bust of Postumus right.
Rev.: HERC DEVS-ONIENSI , Hercules (as the impersonation of the successful emperor) standing right, leaning on club, holding bow and lion's skin.
AGK 25 ; Cunetio 2383 ; Elmer 131 ; Zschucke 118 ; Sear 3111 ; RIC 64 (Bust Type C) .

Hercules Devsoniensi refers to Deuso, a town on the eastern bank of the Rhine river, opposite of Cologne (today called Deutz, it is part of modern Cologne/Köln).
Some say Postumus successfully fought Germanic tribes (the Franks) there and so he hailed Hercules Deusoniensi (ref.: Alföldi, Studien zur Geschichte der Weltkrise des 3. Jahrhunderts nach Christus, Darmstadt 1967, p. 367).