Gallienus, AE23 of Nicaea, Bithynia. 

POY LI EG GALLIHN CEB, Radiate, draped, and cuirassed bust
right
NIKAIEWN, Dionysus, holding cantharus and thyrsus, in 
quadriga of elephants left.

SNG von Aulock 724; BMC 154; Rec Gen 836

Contributed by Jochen of the Forum Ancient Coins, 2009