Gallienus AE25 of Serdica, Thrace.

Obv: AVT K GALLIHNOC, laureate draped bust right
Rev: OVLPIAC (CERDIKHC), one of the Dioscuri standing, 
wearing pileus, holding spear, left hand on hip, chlamys
draped over wrist.

Courtesy of Akropolis Ancient Coins, May 2009.