Constantius I commemorative. Half-follis. 318 AD. Trier. 

DIVO CONSTANTINO OPT IMP, laureate, veiled bust right
REQVIES OPT dot MER, emperor seated left, holding short sceptre, PTR in ex.

RIC VII Trier 206. Extremely rare (R4).

With permission of Roma Numismatics, June 2009