Diocletian AR Argenteus, Siscia. AD 295.

Obv: DIOCLETIANVS AVG, laureate head right.
Rev: VIRTVS-MILITVM, two emperors and two Caesars
sacrificing over a tripod before a gate in an enclosure with six turrets. 

Mintmark star SIS.

RIC VI Siscia 60a; RSC 516+i.
Very rare, rated R4.

With permission of TimeLine Auctions 
(www.timelineauctions.com), Jul, 2017