The Weight Standards of Roman Coins

Before coins were made in Italy or Sicily the native population must have had some means of measuring the bronze which they used as a medium of exchange. The as rude of Central Italy is our earliest link with their primitive system of exchange based on bronze, but it is not very helpful. We do not know when it came into use, although it lingered on some time after the practice of stamping was adopted, for specimens have been found with stamped pieces. The specimens found are sometimes oblong or square, but are frequently quite shapeless. They vary in weight from over 12 pounds to less than 1 ounce, and although at least the amorphous lumps must have passed by weight, we do not know the weight unit employed. ¹ When the practice of stamping ingots of bronze was introduced in Umbria and Central Italy in the middle of the 5th century B.c., the metals were made up into pieces of defined weight. ² During the succeeding century these bulky as signatum were supplemented throughout Northern and Central Italy, Etruria and Latium by heavy round coins (as grave), which offer the first information worth considering as to the weight units for bronze in Italy. It is now fairly generally agreed that these round pieces were based upon the pound or libra of bronze, but it is not easy to determine the size of the libra from an examination of the many specimens of as grave that we possess. ³ They are all cast, and, in consequence, are irregular in weight. But the fact that the libra varied also from district to district ¹ also explains the variety in the weight of the asses. ² In most parts of Etruria, Umbria, and generally in Central Italy, a libra of about 5,045 grains ³ (the “Roman” or “later Roman” pound) was in use from the middle of the 4th century to 268 B.c. Of the other pounds, the most important in its relation to coining was the libra of 4,210 grains (the “Oscan” pound) or ⅚ of the “Roman” unit. A litra unit, comparable to the Italian libra, is believed to have been used in Sicily, but the only evidence of its size is obtained from later silver coins, which are believed to have been worth a litra of bronze. As information as to the relative values of silver and bronze at the time of the introduction of these coins is very speculative, the resulting weights obtained for the litra do not command confidence. ⁴