While the Roman Republic and Empire were centralized bodies of power, the ancient Greek world was split into at least a hundred self-governing towns or city-states; each of which would mint their own denominations of money. Often coins were checked for their metal content and weighed in order to be accepted in other cities, and as coins spread, the weights of the coins became more standardized across the Aegean. However, each city was responsible for their own minting, so standards of weight and worth were never wholly uniform as they were with the later Romans. Each city had unique symbols which could be used to identify the city of origin; Athens, for example, was represented by an owl, an animal that was commonly associated with their patron goddess Athena, while Corinth was represented by dolphins and Rhodes by a rose—a play on words since the Greek word for rose was rhodon.
Greek coins are separated into three periods: the Archaic, the Classical, and the Hellenistic.
The Archaic period is defined by the emerging city-states of ancient Greece, from the introduction of Greek coinage in around 600 B.C. until the wars with Persia in about 480 B.C. These city-states usually included a medium-sized city and the area immediately surrounding it. At this time, there were no Greek empires. Instead, city-states entered into loose alliances ("leagues") which were often easily broken. Two of the most famous examples of city-states are Athens and Sparta, two powerful cities that fought one another in the Peloponnesian War (431-404 B.C.), as chronicled by the contemporary historian Thucydides.
The Classical period is defined as the period from 480 B.C. until the rise of Alexander the Great in the 330s B.C. During the Classical period, some city-states became much grander, with larger spheres of influence. This is reflected in their coinage, which is often more technical and more aesthetically pleasing, and mostly made of gold or silver. They commonly featured a god or goddess on one side, usually the patron god from its city of origin, and a symbol of the city on the other. This was also the period when inscriptions began appearing on coins, often explicitly stating the city where it was minted.
The Hellenistic era, roughly 330 B.C. until the late first century B.C., is commonly referred to as the age of Alexander the Great and his successors. In this era, Greek coinage was spread around the known world when Alexander the Great conquered much of the Eastern Mediterranean and large tracts of western and central Asia. Greek coins became common over vast distances, reaching areas as far east as Sri Lanka and Indochina, and as far west as Great Britain. These were the standard of coinage for centuries to come. After his death, many of Alexander’s successor kings, generals who inherited his empire from Egypt to India, minted coins with their own likenesses and names on them. Because these successor kingdoms were much larger and wealthier than the Greek city states of the classical period, their coins tended to be more mass-produced, as well as larger, and more frequently in gold. In places isolated from the Mediterranean, such as Afghanistan and India, these coins are some of the only evidence of certain Greek occupation and influence, which has otherwise been lost to the sands of time.
As Greek influence increased across Europe and Asia, more and more people began producing coins in the Greek fashion, including the Gauls (the area of modern France), nomads from Central Asia, the inhabitants of India, and the Romans, who refined the Greek design and produced its own distinctive coinage.