Constantine II AE follis of Rome, AD 338-340. 14 mm, 1.8 g. 

VIC CONSTANTINVS AVG, laurel and rosette-diademed, cuirassed bust right.
VIRTVS AVGVSTI, emperor standing front, looking right, holding spear in right hand, and resting left hand on shield.

MintMark R star P.

RIC VIII Rome 21; Voetter 40; ANS 1944.100.20737.

Image courtesy of the ANS, New York.