Constantine I, AR Miliarense. Sirmium, AD 320-324. 20mm, 4.28 g.

CONSTANTINVS MAX AVG, bare head right.
CRISPVS ET CONSTANTINVS, bare heads of Crispus and Constantine II facing 
each other.
Mintmark SIRM.

RIC VII Sirmium 14; RSC 3.
Rare.

With permission of Roma Numismatics, auction IX, lot 827.