The Romans replaced the usage of Greek coins, first by bronze ingots, then by disks known as the
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 were also produced: the (), (), (), (), (), (), (, also a common weight unit), and (), as well as multiples of the
as, the (2), (2), and (3). an as After the
as had been issued as a cast coin for about seventy years, and its weight had been reduced in several stages, a
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
assēs, but in about 140 BC it was retariffed at sixteen
assēs. This is said to have been a result of financing the
Punic Wars. During the Republic, the
as featured the bust of
Janus on the obverse, and the prow of a
galley on the reverse. The
as was originally produced on the
libral and then the reduced libral weight standard. As the weight decreased, the bronze coinage of the Republic switched from being
cast to being
struck. During certain periods, no
asses were produced at all. == Imperial era coinage ==