Aegina was a very important Greek city-state that is almost totally forgotten today. Partially because they were a big player in Greece before Athens, and most of what we know about Aegina is from Athenian records and archaeological studies.
As an island, Aegina was situated between Attica and the Peloponnese, making it a useful island for traders since prehistoric times. There is archaeological evidence of Minoan and Mycenaeans trading with or living on the island. It was really during Archaic Greek period (900s BCE - 480 BCE) that the city-state became a naval powerhouse. It was the first mainland European power to mint its own coins, within 30 or 40 years of the invention of coinage in Asia Minor by the Ionian Greeks or the Lydians (around 630 BCE). It was one of just three city-states, and the only mainland Greek one, trading at and owning a share of the mighty emporium of Naucratis in Egypt. It was a hub for grain from the Pontus region – food always wins, and Pontic grains was so important that Athens would later enforce a monopoly on it.
But to really understand how much of a big-time Aegina was, look at its weights system. The Aeginetic standard of weights and measures (developed during the mid-600s) was one of the two standards in general use in the Greek world. It is like the British Empire making other countries measure in pounds and miles.
