In the late 7th century BC the first coins were produced in the eastern mediterranean. By the early 5th century Greek minting city-states were commonplace. This rapid spread is a clear testament to the newly found usefulness of coinage (money) and that fact alone is enough to justify interest in their study.
But these coins were so much more than an economic convenience. These early coins were produced with a care and artistic craftsmanship on par with all the great artistic productions of the ancient Greek world – these coins are indeed pieces of art. And, in my opinion, the 5th and 4th century coins are the most beautiful coins ever produced.
To create these coins, the artists, called engravers, had to carve their subject matter into metal dies. The dies were then used to strike a heated metal flan, thereby stamping the coin. Eventually the dies would break from repeated use and needed to be engraved again. This explains why so much variation is found in the finer details of these ancient coins, even when the overall subject matter of the coins remained consistent over time.
As an example, these authentic silver Athenian Owls were both minted contemporarily in Athens sometime during the last half of the 5th century BC. A detailed comparison reveals many subtle differences between the two versions (ignoring that somebody, presumably much later, scratched out the identifying letters alpha-theta-epsilon on the upper reverse). They are both beautiful and display an advanced level of craftsmanship and yet one Athena is slightly more beautiful than the other.