Ancient Greek coins are among the most beautiful ever created. They are finely crafted and eloquently display the preeminence of Greek technology and art in the ancient world. They survive today as a lasting and fitting tribute to ancient Greek ideals and culture.
Ancient Greece was not a single kingdom, but rather a loose confederation of independent cities, known as City States. Most City States minted their own coins with designs appropriate to that particular city and its people. For example, coins from Athens typically had the goddess Athena on their obverse side, as she was their patron deity.
Because there were several mints with no universal standard being applied, the weight and precious metal content of a particular coin denomination could vary from place to place. Hence, most merchants in a particular city would only accept the local coins. Visitors would need the services of a moneychanger, who could exchange the visitor's money for coins of equivalent value in the local currency. Typically, moneychangers charged six to seven percent for their services.
Due to its preeminence in commerce, the standards of Athens (the Attic Standard) eventually became predominant and, through the conquests of Alexander the Great, were spread to much of the ancient world.
Most Greek coins were made of silver, although there are examples struck in bronze/copper, gold, and electrum (a naturally-occurring alloy of gold and silver, also known as "white gold"). Printed letters forming legends and mottos are usually absent from ancient Greek coins and, when lettering does appear, it tends to be quite minimal.
Among the coins produced by the ancient Greeks are the following denominations:
Chalkos - these were copper coins of little value. Eight of them were worth an Obol.
Obol (Obolus) - In the days before coins, these were elongated iron rods, apparently used for cooking (Obolus literally means "spit" or "iron rod"). Later, the Obol became a silver coin whose value, presumably, was equivalent to one such rod. Coins were minted representing a fraction of an obol (e.g., the hemiobol was worth one half obol) and multiples of obols (e.g. diobols were worth 2 obols, triobols were worth 3 obols, and tetrobols were worth 4 obols).
Drachma - a silver coin worth literally a handful of obols (drachma = "a handful"). In classical Athens a Drachma was worth six Obols. The Drachma was the standard silver coin in most Greek cities. Coins were minted representing multiples of the Drachma (e.g., Didrachma and Tetradrachma).
Stater - the Stater was a silver coin worth two or three Drachmas.