It was one of a large number of coins issued for the Ludi Novae Saeculares ("Games of the New Age" or the "Millennial Games") of AD 248, which marked the 1,000th anniversary of Rome's foundation. I think it's also interesting because of the use of the officina mark on the reverse, one of the first issues to do so. I happen to like the reverse design itself, apart from its historical significance. Let's see your Millennial Games issues of Philip, coins you won at yesterday's Savoca auction, or anything you feel is relevant. Philip I, AD 244-249. Roman AR Antoninianus, 23mm, 3.93 g, 7h. Rome mint, 5th officina, 8th emission, AD 248. Obv: IMP PHILIPPVS AVG, radiate, draped, and cuirassed bust right. Rev: VIRTVS AVGG, Philip I and II on horseback galloping right; Є below. Refs: RIC IV 10; RSC 241a; RCV 8976; Hunter 43.