In my current reading, The Last Pagan: Julian the Apostate and the Death of the Ancient World, Adrian Murdoch mentions that in the early 4th century AD, Constantine initiated a new coin for the Roman Empire, the aureus, for the Latin word for gold.
Roman coinage is a complicated area — for numismatic specialists combining proficiency in art history, law, economics, epigraphy, and ancient history — that I have long avoided. Today I’m making a quick and tangential foray into this treacherous territory and posting what information I can forage.
Constantine’s aureus was only one in a long history of coins stretching back from the third century B.C. Before there were coins, the Italians used cattle for money (pecunia).
Around 300 B.C. coinage started in Rome. The early metal used for currency wasn’t actually coined. It was lumps of bronze, aes rude.
Next came aes signatum, marked bronze, either stamped or cast, chopped up, and therefore sometimes indistinguishable form the lumps. These were the responsibility of the iiiviri of the mint, a new office created at the end of the Samnite Wars in 289 B.C.
After aes signatum came aes grave, which were cast bronze with their value imprinted on their face, as well as the place where they were issued.
The unit of weight for the aes grave was the bronze libra which could be divided into 12 unciae. This bronze libra was called an as by the Romans. [Notes to self: (1) was it called an as because that’s the Roman pronunciation of aes? (2) when is the term as used and when libra?]
The Romans marked the coins with the name Roma and when the coins were struck, they had heads of gods on them. Specifically, in one series of coins from large to small, the as had a Janus, the semis, a Jupiter, the triens, a Minerva, the quadrans, a Hercules, the sectans, a Mercury and the uncia, a Roma. This is referred to as the Janus-prow series. [Notes to self: (3) learn which side is obverse, which side had the god, and which side had the prow on it. (4) is a triens a third of an as, a quadrans, a fourth, a sectans, a sixth, and an uncia, an eighth?]
In 269, Livy and Pliny say silver came into use in Rome, and the argenteus or quadrigatus was first struck. When silver coins came in they were based on the Greek drachma standard. A new silver coin was probably valued at 10 asses. This was later known as the denarius. This may have been what Pliny called the argenteus. Durng a financial crisis of Punic War II, the value of a libra was reduced, the denarius replaced the quadrigatus and was given a fixed value by being marked with an X for 10 bronze asses. The quadrigatus were thereafter called bigatus from a biga-riding Diana on one such coin.
“Roman Currency under the Republic,” by Edwin W. Bowen. The Classical Journal, Vol. 47, No. 2, (Nov., 1951), pp. 92-97.
“The First Age of Roman Coinage,” by H. Mattingly. The Journal of Roman Studies, Vol. 35, Parts 1 and 2, (1945), pp. 65-77.
“The Problem of the Early Roman Coinage,” by J. G. Milne. The Journal of Roman Studies, Vol. 36, Parts 1 and 2, (1946), pp. 91-100.