As Severus Alexander - Restitutor monetae
SEVERUS ALEXANDER. Æ Dupondius. Rome, mid to end 228 AD.
Obv. IMP SEV ALEXANDER AVG radiated and bust right with aegis
Rev. RESTITVTOR MON SC emperor staging l. in military dress, holding scepter and extending right hand.
RIC 601 (S); Cohen 516 (10 F)
RIC IV p. 66-67 states that this issue of Dupondii seems to allude to some kind of monetary reform for which the emperor was responsible. But as the general character of Alexander's coinage is similar to that of his immediate predecessors, it is difficult to discover any clear indications of a monetary reform. It seems then more likely that the type refers to a reorganization of the mint of Rome.
Jerome Mairat classified the emissions of Alexander and considers this one to have occured between mid and end 228 AD (see http://www.inumis.com/rome/articles/alexandre/alexandre3-fr.html ).
Nice mid-green patina.