Ancient Greece
After the Persians' defeat at Platea, the Spartans did very little. However, Persia was still dangerous. Athens asked the Greek city-states on the islands in the Aegean and in Anatolia to join it. They agreed because they were afraid of Persia and formed the Delian League and Athens was their leader. Many of the city-states of the Delian League had to pay Athens tribute money. Athens used it to build many ships and the Parthenon. During the Peloponnesian War, Sparta was still strong on land, but Athens was stronger on the sea. Several times, there was war between Athens and Sparta. Athens then decided to send many ships to Sicily to Syracuse.  Sparta sent help to Syracuse, and Athens was defeated. None of the Athenian ships came back.