Constantine I AE Follis. London mint, AD 312-313. 

IMP CONSTANTINVS P AVG, laureate, cuirassed bust right.
MARTI CON-SERVATORI, Mars standing right, helmeted and 
in military dress, cloak spread over upper chest, holding 
upright spear, point downwards, left hand on shield. 

Star in left field. 
Mintmark PLN. 

RIC VI London 252.
Rare.

With permission of Roma Numismatics, March 2014.