Caracalla Denarius Ancient Roman Empire Silver Coin 206AD RIC 83a

Obverse: ANTONINVS PIVS AVG, Head of Caracalla, laureate, right
Reverse: PONTIF TR P VIIII COS II, Mars, helmeted, in military attire, standing left, resting right hand on shield and holding spear in left hand
Date: 206 A.D.
ID: RIC IV Caracalla 83a
Size: 19.5mm diameter, 3.39g weight
Composition: Silver

Mars was the Roman god of war.

Caracalla was a cruel and tyrannical leader according to ancient historians. He and his brother Geta became co-emperors in 211 A.D. upon their father's death. The two brothers had a fierce hatred of one another, which culminated in Caracalla having Geta stabbed to death later that year and declaring himself sole emperor (then massacring 20,000 of Geta's friends and supporters). 

Caracalla spent nearly his entire reign campaigning with his armies, and styled himself a soldier-emperor. He met his end in 217 A.D. (29 years old) at the sword of a common Roman soldier, who was angry that Caracalla had not approved his promotion to centurion (and who was possibly encouraged/aided in the assassination by Caracalla's general Macrinus, who became the next emperor).