Herennius Etruscus. AR Antoninianus. 20 mm, 4.23 g. AD 249-251. Rome. 

Q HER ETR MES DECIVS NOB C Radiate and draped bust right.
MARS PROPVG, Mars walking right, holding spear with his right hand and shield with his left.

RIC 140. 
Very Rare.

With permission of Nomos AG obolos 6, Lot 863, Nov. 2016.