The city of Athens during the classical period of Ancient Greece was the major urban center of the notable polis 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. The peak of Athenian hegemony was achieved in the 440s to 430s BC, known as the Age of Pericles. In the classical period, Athens was a center for the arts, learning and philosophy, home of Plato's Akademia and Aristotle's Lyceum, Athens was also the birthplace of Socrates, Pericles, Sophocles, and many other prominent philosophers, writers and politicians of the ancient world. It is widely referred to as the cradle of Western Civilization, and the birthplace of democracy, largely due to the impact of its cultural and political achievements during the 5th and 4th centuries BC on the rest of the then known European continent.