The city of Athens during the classical period of Ancient Greece (508–322 BC) was the major urban center of the notable polis (city-state) of the same name, located in Attica, Greece, leading the Delian League in the Peloponnesian War against Sparta and the Peloponnesian League. Athenian democracy was established in 508 BC under Cleisthenes following the tyranny of Isagoras. This system remained remarkably stable, and with a few brief interruptions remained in place for 180 years, until 322 BC (aftermath of Lamian War). The peak of Athenian hegemony was achieved in the 440s to 430s BC, known as the Age of Pericles.