What is "dupondius"

n. A bronze coin minted during the Roman Empire and Roman Republic, equal to 2 as.

The dupondius ( Latin two-pounder) was a brass coin used during the Roman Empire and Roman Republic valued at 2 aes (1/2 of a sestertius or 1/8 of a denarius).

The dupondius was introduced during the Roman Republic as a large bronze cast coin, although even at introduction it weighed less than 2 pounds. The initial coins featured the bust of Roma on the obverse and a six-spoked wheel on the reverse.

With the coinage reform of Augustus in about 23 BC, the sestertius and dupondius were produced in a golden colored copper-alloy called orichalcum by the Romans and numismatists, and Latin brass by us, while lower denominations were produced out of reddish copper. However, some dupondii were made entirely from copper under Augustus, while under subsequent Nero some aes were made from both orichalcum and copper, instead of only copper for aes coined until then. Therefore, the latter can only be distinguished from dupondii by their smaller size instead of by also the appearance of the metal.

The dupondius was normally further distinguished from the similarly sized as with the addition of a radiate crown to the bust of the emperor in 66 AD during the reign of Nero. Using a radiate crown to indicate double value was also markedly used on the antoninianus (double denarius) introduced by Caracalla and the double sestertius. Since dupondii minted prior to and during the reign of Nero, and occasionally under later rulers, lack the radiate crown, it is often hard to distinguish between the as and the dupondius due to heavy patina which often obscures the coin's original color.

An extremely rare dupondius from the reign of Marcus Aurelius, dated to AD 154 or 155 and in excellent condition, was discovered in 2007 at the archeological site in Draper's Gardens, London.