The Peloponnesian War

The Peloponnesian War (431–404 BCE) was the great civil war of the Greek world, pitting the Athenian-led Delian League against the Spartan-led Peloponnesian League in a conflict that devastated Greece and ended Athenian supremacy. It was, in Thucydides' famous assessment, 'the greatest disturbance in the history of the Hellenes.'

The war's immediate cause was Athenian imperialism. After the Persian Wars, Athens had transformed the Delian League — originally a defensive alliance against Persia — into an Athenian empire. Tribute payments that were supposed to fund a common navy were diverted to build the Parthenon. Allies who tried to withdraw were crushed. Sparta, wary of Athenian power and ideologically opposed to its democratic system, eventually went to war.

The conflict lasted 27 years and went through several phases. Athens' plague (which killed Pericles), the disastrous Sicilian Expedition, and Sparta's alliance with Persia all proved decisive turning points. Sparta's final victory in 404 BCE destroyed Athenian power, but Sparta proved equally incapable of managing Greece. The real winner was Philip of Macedon, who exploited the weakened, divided Greek city-states to establish Macedonian dominance a generation later. Thucydides' history of the war remains one of the greatest works of political analysis ever written — a study of how fear, honor, and interest drive nations to self-destruction.