Septimius Severus, AE30 of Perinthos, Thrace.

AV K L CEP CEVHROC P, laureate head right.
PERINQIWN NEWKORWN, Poseidon, naked, standing right, 
holding dolphin and trident.

Varbanov 189 (this coin).

Courtesy of Antike Muenzen Auction, May 2001.