Caracalla, AE30 of Serdica, Thrace. 

AVT K M AVP CEVH ANTWNEINOC, laureate, draped, cuirassed bust 
right, seen from behind.
OVLPIAC CERDIKHC, Athena, helmeted, standing right, 
holding spear and feeding a serpent which is entwined around
tree to right.

Varbanov 2228 (this coin).

With permission of Numismatik Lanz, auction 2002.