Constantius II, AV solidus, AD 347-350. 

FL IVL CONSTAN-TIVS PF AVG, rosette and pearl-diademed, draped, cuirassed bust right.
GLORIA REI-PVBLICAE, Roma seated on the left, head facing, 
Constantinopolis seated left on the right, looking left, left 
foot on prow, holding between them a shield inscribed VOT XX 
MVLT XXX. Roma's right hand is beneath the shield. 

Mintmark SMAN Delta. 

RIC VIII Antioch 84.

Heritage World Coin Auctions - New York Signature Sale 3030, Jan. 2014.