The city of Aegina was the capital of the island of the same name, in the Saronic Gulf across a narrow strait from Athens. The city was an early commercial center, and it was regarded by the Athenians as a rival and an enemy.

According to legend Aegina was a daughter of the river-god Asopus. Zeus carried her off to the island named for her, despite the efforts of her father to prevent it. Once there the result was Aeacus, the most pious of men. As Aeacus was alone there Zeus turned ants into men for his companions and servants; hence the so-called Myrmidions, according to Apollodoros.

Whatever the legends, by the seventh century Aegina had become one of the most powerful Greek naval states. Its commercial power was also legendary; hence the production of the first coinage in Europe, the turtle-stater, around 550 BC.. In Greek legends the sea-turtle was a ferocious monster, rather like a shelled shark; hence the emblem is symbolic of sea power, much as the lion or boar is of land power.

The power of Aegina excited the envy of Athens, which carried on a rivalry by fair means and foul. When the Greeks united against the Persian threat the Aeginitans provided a contingent which was acclaimed as the best fighters in the fleet; shortly thereafter, however, the envy of the Atenians of what Pericles called the eyesore of the Piraeos resulted in a war in 459. Aegina was captured ad forced into the Athenian Confederacy.

In 431 BC the Aeginitans conspired with Sparta against their allies; as a result the Athenians took the city again, and expelled the inhabitants. With the fall of the Athenian power in 405 the Spartans restored them, but the city never regained its position.