Constantine. AE half-follis. 310-311 AD. Trier. 

CONSTANTINVS AVG, laureate, cuirassed bust right
MARTI-CONSERV, Mars, helmeted, standing right, 
holding reversed spear and left hand resting on 
shield on ground. PTR in ex. 

RIC VI Trier 897. Scarce.

With permission of Roma Numismatics, August, 2009