Diadumenian denarius, struck AD 217-218 at Rome mint. Obv: M OPEL ANT DIADVMENIAN CAES , bareheaded and draped bust right. Rev. PRINC IVVENTVTIS, Diadumenian standing facing, head r., holding standard in r. hand and sceptre in l.; in field r., two standards. 3,28 g, 20 mm. RIC 102