The adoption of coined money stemmed from the mutual influence of two different types of media of exchange: weighed metals and utensil-money. While the countries under the influence of Assyrian and Egyptian culture were using as currency precious metals measured by weight on the basis of the mina and its multiples and submultiples, the Greeks of the Dark Ages were using utensil-money counted by units in which shape and not the intrinsic content of metal was relevant. Utensil-money tended to be made of the cheapest possible metal fit for an object of the desired appearance and shape. There are reasons to believe that the currency of double axes mentioned in the Homeric poems was of cast iron; the limited use of iron in the Homeric culture may be explained by the circumstance that cast iron, and not wrought iron, was then known. The Spartan iron money of historical times, too, was of cast iron; this may have been a survival of an earlier general use of cast iron for the manufacture of utensil-money.
In the seventh century B.C. weighed silver began to be used in Greece as a medium of exchange; this silver was measured on the basis of the mina and its sexagesimal submultiple, the shekel, according to the Babylonian-Assyrian method of reckoning. In the Peloponnese, weighed silver currency came into competition with the established currency of iron obols. Obols were a form of utensil-money consisting of the spits used for broiling meat on the open fire: they were an object of daily use down to classical times, not only in Greece, but also in Italic, Etruscan, and Celtic territory. A relation of value was established between the iron obol and weighed silver: six iron obols, that is a drachma, were considered equal to a shekel of silver. This relation was called mevtra, which means ratio and is synonymous with ajriqmov". By the establishment of this relation, the concept of a continuum measured by weight was extended from the silver currency to iron, so that an iron obol came to be considered equal in value to a piece of iron in any shape, provided the weight was identical. This equivalence was dramatized by setting up at the Heraion of Argos, probably on the opposite sides of a balance, a bundle of 180 iron obols of traditional shape and a solid iron lingot having the same weight as the bundle. The 180 iron obols, and likewise the solid iron lingot, had a value of half a silver mina. The particular silver mina used as a unit was known as the Euboic mina and became the basis of all Greek monetary standards; the name Euboic is derived from Euboia, the name of the location of the Heraion, not from the island of Euboia. There resulted a bimetallic system of currency in which both iron and silver were measured by weight. The short thick iron bars found at the temple of Artemis Orthia in Sparta are an example of the new obol in which weight and not shape was the telling factor. However, bimetallism did not last long and silver remained the only currency in Greece, with the exception of Sparta and a few lesser cities where iron remained the only legal currency. The disappearance of one or the other currency from the market may be explained by Greshams law: the same relation of value which made iron a good currency in the rest of Greece made silver a good currency in Sparta where iron was cheaper.
Close examination of the cuttings in a fragment of inscribed stone found at the temple of Hera Limenia at Perachora reveals that it was a part of the base of a balance used to weigh iron currency. Pottery sherds found with the stone reveal that the balance ceased to be used around 600 B.C. and thus suggests that iron currency was not used beyond that time.
In the period in which both iron and silver were in circulation, it was found that silver, being less bulky, was preferable to a quantity of iron of the same value, that is, that silver was at agio over iron. The agio was taken into account by asking the party who traded it to add an extra amount, so that it took seventy iron drachmae, and not sixty, to make up the acceptable equivalent, and hence the real value of a silver mina. This modified relation was called feidwvneia mevtra, short relation, because by it the party who exchanged iron for silver received less silver than it would have received if agio had not been considered. At a later time, when iron was no longer used as currency, the adjective feidwvneio" was understood as a reference to a ruler called Pheidon. The economic factor of agio explains why many weights of the ancient world existed in a heavy and in a light variety: the heavier variety was used to weigh commodities which were less desirable from the point of view of easy handling. In Athens, units used to weigh all commodities other than silver were heavier than those used to weigh silver, because silver had the advantage of being the accepted medium of exchange.
The original meaning of the word novmisma is not that of coin, but that of accepted standard of value. The word was first used in the fifth century B.C. as a doublet of novmo". For this reason, to clarify the concept of novmisma it is necessary to clarify that of novmo". Novmo" is not to be taken as the counterpart of the Roman lex, but represents a peculiarly Greek conception of what is accepted without compulsion as the standard of right in a given community. The idea of a society based on a system of socially established standards is a key to the understanding of Greek thoughts in the field of jurisprudence, political theory, and economic doctrine.
Once the meaning of the words novmisma and novmo" is clear, the interpretation of the passage concerning the monetary reform of Solon is no longer open to dispute. All that Solon did was to abandon the feidwvneia mevtra based on the sexagesimal division of the mina, and to make the drachma equal to the half kedet, one hundredth of a mina, according to the Egyptian decimal system of reckoning. This reform had to do with political relations with Egypt, because on the eve of Solons reform a bundle of obols, similar to that of the Argive Heraion, was set up in front of the temple at Delphi by Nitokris, divine consort (eJtaivra) of Psammmetichos II of Egypt. The conclusions reached concerning the Solonian reform agree with the evidence afforded by coins and by reference weights found in Attica. They also contribute to the solution of the much-disputed problem of the Aeginetan mina. The Aeginetan mina is a hybrid creation of the Athenian market, achieved by taking the pre-Solonian drachma, equal to the Aeginetan drachma, which is a modified sexagesimal submultiple of the mina, and giving to it a centesimal multiple, according to Solons centesimal division of the mina.
From the results reached concerning Greek technical terms in matters of coinage, it follows that the Athenian decree concerning the striking of coins by members of the Athenian League did not forbid the allied cities from issuing coins, as is currently believed, but merely ordered them to issue coins according to Athenian standards. This interpretation is in agreement with numismatic evidence and does away with the need of assuming that the decree was passed but not enforced.