Constantius II, AR Siliqua. Heraclea. AD 340-351. 

DN CONSTANTIVS AVG, laurel and rosette diademed, draped 
and cuirassed bust right
FELICITAS REIPVBLICE around VOT XV MVLT XX in four lines 
within wreath.
Mintmark SMH.

RIC VIII Heraclea 40 var (XV..XX not XX..XXX); Sear 17900 var 
(ditto)