Marcus Julius Philippus, also known as Philippus I Arabs, succeeded Gordian III in AD 224. Philip arranged a treaty with Persia and returned to Rome where he appointed his young son Philip II as Caesar. The following year Philip II was advanced to the rank of Augustus. In AD 248, the year of Philip's third consulship, the millennium of Rome was celebrated and featured on the coinage from Philip's reign. The reverse type legend often read SAECVLARES AVGG. Coins struck between AD 244 and 248 bear the long obverse legend displayed on the dupondius above - a shortened obverse legend followed later issues.
In AD 248 Philip sent Trajan Decius to suppress the revolt in Moesia - this resulted in the latter being proclaimed emperor. The next year Philip was defeated and he died in battle at Verona.

Obv. Philip I, radiate bust, IMP. M. IVL. PHILIPPVS AVG.

Rev. Cippus inscribed COS. III. SAECVLARES AVGG. The coin alludes to the millenary anniversary of Rome in AD 248.