
At the beginning of the archaic period, coinage had not yet been invented. The Greeks measured the value of objects or fines using certain valuable objects, such as oxen, tripods, and metal spits, as units of account. As in the Near East, precious metal bullion was used as a medium of exchange, principally gold at first, but mainly silver by the beginning of the sixth century. The weight of this bullion (often known as hacksilber) was measured using standard units, named for their value in terms of metal spits (obeloi) and handfuls (drachmai) of metal spits; these terms would later be used as names for Greek coin denominations.
Coinage was invented in Lydia around 650 BC. It was quickly adopted by Greek communities in western Asia Minor, although the older system of bullion remained in use as well. The island of Aegina began to issue its distinctive “turtle” coins before 550 BC, and from there coinage spread to Athens, Corinth and the Cycladic Islands in the 540s BC, Southern Italy and Sicily before 525 BC, and Thrace before 514 BC. Most of these coinages were very small and were mostly only used within the community that issued them, but the “turtles” of Aegina (from 530 or 520 BC) and the “owls” of Athens (from 515 BC) were issued in great quantity and exported throughout the Greek world.
The images on coins initially changed rapidly, but increasingly each community settled on a single image or set of images. Some of these were the symbol or image of an important deity in the city or visual puns on the city’s name, but in many cases their meaning is obscure and may not have been chosen for any special reason.
The reasons for the rapid and widespread adoption of coinage by the Greeks are not entirely clear and several possibilities, which are not mutually exclusive, have been suggested. One possibility is the increased ease of commerce which coinage allowed. Coins were of standardised weights, which meant that their value could be determined without weighing them. Furthermore, it was not necessary for users of coinage to spend time determining whether the silver was pure silver; the fact that the coin had been issued by the community was a promise that it was worth a set value. Another possibility is that coinage was adopted specifically to enable communities to make payments to their citizens, mercenaries and artisans in a transparent, fair and efficient way. Similarly, when wealthy members of the community were required to contribute wealth to the community for festivals and the equipment of navies, coinage made the process more efficient and transparent. A third possibility, that coinage was adopted as an expression of a community’s independence and identity, seems to be anachronistic.
Source: Wikipedia

