Constantine, Rome, AE Follis. 

IMP CONSTANTINVS P F AVG, Laurate bust
SOLI INV-I-CT COM D M , Sol, radiate, standing left, raising 
right hand, holding Victory on globe in left. 
Star in left field; straight line (should be a crescent) in right field.
Mintmark RT

RIC VII Rome 49 var (field mark - instead of crescent)

Notes: There should be a crescent in the right field. This 
coin clearly has a flat line instead.

Contributed by Glenn Simonelli, March 2011