I do not see he is cuirassed,but on description.... Pupienus AE Sestertius, RIC 22a, Cohen 23, BMC 48
Pupienus Æ Sestertius. IMP CAES M CLOD PVPIENVS AVG, laureate, draped & cuirassed bust right / PAX PVBLICA, SC in ex, Pax seated left, holding branch & scepter. Cohen 23.

