Early Romans replaced a cattle standard with a raw copper or bronze metallic standard. Various authors report the standard as copper or bronze, depending upon the translation of the Latin, which apparently used the same word to refer to both copper and bronze. This metal was used to make farm implements, rendering it valuable as money when the Romans changed from a pastoral to an agricultural society. The Romans remained on a bronze standard until the end of the Republic in 30 b.c.
The earliest bronze money, called aes rude, consisted of rude chunks of raw copper or bronze. These chunks began circulating as money while the Romans were on a cattle standard and were in use during the sixth century b.c. Specimens of this currency range in size from over 12 pounds to less than one ounce, and sometimes have an oblong or square shape. They must have been valued on the basis of weight.
During the fifth century b.c. a bit more refined form of bronze (or copper) money appeared, called aes signatum. This money took the form of regularly shaped bronze (or copper) bars with a specific weight. In the beginning one aes equaled a pound of bronze (or copper). These bars were stamped with an impressive variety of figures, including oxen and sheep, perhaps to create a psychological link between the new metallic money and livestock money. Swords, tripods, anchors, the Roman eagle, and fishbone-like markings are among the list of figures found on these bronze (copper) bars. During the fourth century b.c. the Romans began casting heavy round coins, known as aes grave. These coins, definitely circulating under the auspices of the government, came in sizes of various fractions or multiples of a pound of bronze (or copper), and often bore the image of a sheep, cow, or hog.
With the enactment of the Tarpeian law of 454 b.c., the government began the official transition to a metallic currency, providing that fines assessed in terms of cattle or sheep might be paid in the form of marked copper or bronze.
The weight of the aes steadily fell. According to Pliny, during the first Punic War in the third century b.c., “the Republic not having means to meet its needs, reduced the aes to two ounces of copper; by this contrivance a saving of five-sixths was effected, and the public debt liquidated” (Frank, 1959). During the second Punic War the weight of the aes was reduced to one ounce, and in 87 b.c. it was reduced to half an ounce to help pay for the Social War, a civil war that led to the end of the Republic.
The Roman language of money left an impressive legacy on our modern languages. The bronze coins were called pecunia, a reference to the images of livestock stamped on them. Pecos was the Latin word for cow, and in English money considerations are nowadays called pecuniary. The Latin word for pound, libra, was the predecessor of the English pound, the French livre, and the Italian lira. The word expenned meant “weighed out,” referring to the weighing of the asses in payment for goods. The English words “money” and “mint” evolved from the word moneta, the Latin term for the coins struck at the Senatorial Mint located in the Roman temple for the goddess Juno Moneta. Also, the English words “estimate” and “esteem” came from the Latin aestumare, meaning “to value in copper.”
During the third century b.c. the Romans began coinage of silver. These coins were struck, rather than cast, as the bronze coins had been. (Struck coins are stamped with hammers and cast coins are melted in molds.) By the middle of the second century b.c. bronze coins had lost much of their importance, and Augustus put the Romans on a bimetallic gold and silver standard in the last century b.c.