The coin shown is either a poor original (unlikely) or barbarous radiate antoninianus (minted in Gaul or Britain) of the late 3[SUP]rd[/SUP] Century e.g. circa AD 270-275. The actual emperor GALLIENUS coin of circa AD 265-266 would have Obverse GALLIENVS AVG Radiate head right and Reverse PROVID AVG with Providentia standing left holding globe and transverse sceptre with an officina mint mark in the exergue (e.g. M P for Milan). Actual coin is listed under SEARS vol III 10331.