The Battle of the Eurymedon took place between the Athenian-led Delian League and Persia on the Eurymedon River in Pamphylia in Asia Minor. The specific date is unknown, but it was between 470 BC and 466 BC.
The Greeks, led by Cimon of Athens, actually defeated the Persians at two separate battles on the same day, first on the river and then on land. The Persian navy, consisting of 200 Phoenician ships, was completely destroyed in the naval portion of the battle. After this victory, Cimon landed and attacked the Persian camp, destroying it as well. The cities of Caria and Lycia (such as Cnidus) became allies (or subjects) of the Delian League, and Persia was unable to invade Greece for a third time. The loot taken from both the Persians and from Athens’ new allies allowed them to expand the Acropolis.