As (monetary unit)

The as (plural asses), also assarius (rendered into Greek as ἀσσάριον, assarion) was a bronze, and later copper, coin used during the Roman Republic and Roman Empire.

The Romans replaced the usage of Greek coins, first by bronze ingots, then by disks known as aes rude. The system thus named as was introduced in ca. 280 BC as a large cast bronze coin during the Roman Republic. The following fractions of the as were also produced: the bes (2/3), semis (1/2), quincunx (5/12), triens (1/3), quadrans (1/4), sextans (1/6), uncia (1/12, also a common weight unit), and semuncia (1/24), as well as multiples of the as, the dupondius (2), sestertius (2.5), tressis.

After the as had been issued as a cast coin for about seventy years, and its weight had been reduced in several stages, a sextantal as was introduced (meaning that it weighed one-sixth of a pound). At about the same time a silver coin, the denarius, was also introduced. Earlier Roman silver coins had been struck on the Greek weight standards that facilitated their use in southern Italy and across the Adriatic, but all Roman coins were now on a Roman weight standard. The denarius, or 'tenner', was at first tariffed at ten asses, but in about 140 B.C. it was retariffed at sixteen asses. This is said to have been a result of financing the Punic Wars.

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