VALERIAN I
AR Antoninianus  253-260  A.D.
O:  Radiate, draped bust right.  IMP C P LIC VALERIANVS AVG.
CONCORDIA AVGG, Clasped hands.

Hybrid with a reverse of Gallienus. There are a number of these 
known from the sole reign (sole reign obverse/joint reign reverse); 
however, since this obverse legend and reverse date from the very
beginning of the reign, that would not seem to be a feasible explanation.
A look at RIC V shows us, with the obverse legend IMP C P LIC 
VALERIANVS (or GALLIENVS) AVG paired with twelve AVGG reverses, 
roughly eight for Valerian and four for Gallienus, not counting 
minor variants in spelling, etc., attributed to 253 AD. 

Contributed by Stephen Coulter, April 2000