Dupondius Coins

"Dupondius" translates from Latin as "two-pound." Its mammoth weight requires understanding of the Roman system of weights and measures. The as, the lowest denomination of Roman coinage, was originally designed as a one-pound weight; with time, it became a thin copper disk of little weight. The dupondius, twice the value of the as, was intended to be twice as big. But according to www.economicexpert.com and www.unc.edu/~rowlett/units/ (both of which contain fascinating histories of coinage and weights), the Roman pound weighed roughly 7/10 of an English pound--still a heavy load to carry for trade or shopping!

It is from the Roman "libra" that we get our "lb." abbreviation for pound. Dupondii were cast from a gold-colored bronze alloy. During Nero's reign (66 AD), double value was indicated by a radiate crown on the emperor's portrait on the coin. This doubling signal was applied to the denarius and sestertius as well, into the third century.