Did the Athens form an alliance called the Delian League?
Yes. The Delian League, an Athenian alliance, was founded after the Persian Wars as a military organization directed against the Achaemenid Empire, but converted by the Athenian politician Pericles into an Athenian empire. The Spartans launched the Peloponnesian War (431-404) to force the Athenians to give up the Delian League.