Helena, mother of Constantine I. Æ follis (3.10 gm). 
Struck 325-326 AD. Heraclea

FL HELENA AVGVSTA, diademed and mantled bust right
SECVRITAS REIPVBLICE, Securitas standing left, holding 
branch pointing down, raising robe with right hand;
Mintmark: dot SMHB. 

RIC VII Heraclea 95. 

With permission of Numismatik Lanz, Munich