Diocletian AE Antoninianus. Rome. 285-286 AD.

Obv: IMP DIOCLETIANVS AVG, radiate, draped, cuirassed bust right
seen from the back.
Rev: IOVI CONSERVAT AVGG, Jupiter standing left, holding thunderbolt
and sceptre.

Mintmark XXIB

RIC V-2 162 Rome.

Courtesy of "the_Apostate" of the Forvm. April 2010.