Ancient Greek Gold Coin of Zeugitana
Circa 270-240 BCE

During the sixth century BCE, the widespread adoption of coinage by the Greek world fostered the introduction of designs which referred to the authority of the city-state that minted them.  The city-state's authority guaranteed the quality and value of the coins and protected them against abuses, such as forgery.  Many of the designs chosen by the city-states to represent their authority symbolized their religious cults or myths.  

This ancient Greek gold coin of Zeugitana, minted in Carthage between 270 and 240 BCE, bears the head of Persephone, the daughter of Demeter, the goddess of fertility, agriculture, and marriage on one side and a free horse associated with the goddess on the other.  Most of the Greek coins were silver.  The fact that this coin was minted in gold reflects the availability of gold in this region.  

It is unknown exactly why the Greek city-states changed from measured pieces of silver to stamped coins in the sixth century BCE.  Herodotus, in the fifth century BCE, suggested that this change occurred for economic reasons: it was easier to use coins to trade both within the community and outside it.  Many Greek coins of this era have been found in regions as far away as Egypt, the Near East, and the Black Sea showing that they were popular in long distance commerce.  

In the fourth century BCE, the philosopher Aristotle wrote in his treatise, The Politics, that it was simply for convenience, to save the hassle of weighing the silver pieces out for every trade or financial transaction.  It has also been suggested by historians that coins were issued by Greek city-states or rulers in order to meet various payments, such as civil and military expenditures.  

In addition, the city-state placed a value on the coins that it issued which was higher than the value of the bullion from which they were made, thereby enabling the government to accrue considerable revenue.  This proved most successful in city-states that had a strong balance of trade in their favor.