Reason for rise in power
After the Persians had been defeated and the Spartans had gone home, Athens and the other Greek city-states formed a new alliance at the Island of Delos in 477 B.C. Accordingly, this new confederation was called the Delian League, and each city-state would contribute men, ships, and money to the League for protection. As time progressed, Athens began to dominate the Delian league and took advantage of its allies' desire to stop sending ships and men. As a result, the members of the Delian league contributed money to the league rather than ships. This benefitted the Athenians greatly because it meant that they were increasing their military presence within the league, while the other members were weakening. Eventually, Athens moved the League treasure from Delos to Athens.