Caracalla AE30 of Serdica, Thrace. 

AVT K M AVR CEV ANTWNEINOC, Laureate head right.
OVLPIAC CERDIKHC, Helios, radiate and with cape 
flowing behind, advancing left, holding whip in right arm, 
raising right hand. 

Varbanov 2318 (this coin); Ruzicka 155; Moushmov 4905.