Greece in the 5th century BC BC, the Greeks, under the Spartan Pausanias, defeated the Persian army at Plataea. The Athenian fleet then turned to chasing the Persians out of the Aegean Sea, defeating their fleet decisively in the Battle of Cape Mycale, and in 478 BC the Athenian fleet captured Byzantium. In the course of doing so Athens enrolled all the island states and some mainland allies into an alliance, called the Delian League because the League's treasury was kept on the sacred island of Delos. The Spartans, although they had taken part in the war, withdrew from any further involvement, allowing Athens to become
Greece in the 5th century BC Peloponnese, winning battles at Naupactus (429 BC) and Pylos (425 BC). But these tactics were not able to provide either side with a decisive victory. After several years of inconclusive campaigning, the moderate Athenian leader Nicias concluded the Peace of Nicias (421 BC). In 418 BC, however, hostility between Sparta and the Athenian ally Argos led to a resumption of fighting. At Mantinea Sparta defeated the combined armies of Athens and her allies. The resumption of fighting brought the war party, led by Alcibiades, back to power in Athens. In 415 BC Alcibiades persuaded the Athenian Assembly to launch a