Picked this coin recently at a local auction site. RIC 73, Rome. It even deserves a separate entry in Failmezger's book, No. 399, RR.
Primary attribution: RIC VIII 73 Rome var R
Date: 347 AD
Obverse: CONSTANS PF AVG, Rosette-diademed draped cuirassed bust right
Reverse: VICTORIAE DD AVGG Q NN, Two Victories facing with heads turned toward one another, each holding a wreath, RQ in ex. (probably) No Legend Break