Caracalla, AE Sestertius. AE 32.4mm, 25,40 gr. Struck 212 AD. 

Obv: M AVREL ANTONINVS PIVS AVG BRIT, laureate head right.
Rev: (PM TRP) XV COS III PP, Mars standing left, holding 
Victory and spear; captive seated at foot left.

RIC 490 var (consular year); Cohen 198 var (same).
RIC lists only ..COS IIII PP for this reverse and obverse.

courtesy of Asta Tintinna Numismatica and deamoneta.com, Dec, 2010 (Auction 26.12.10, lot 2027)