Peloponnesian War

The Peloponnesian War was fought from 431 to 404 BCE between the Athenian-led Delian League and the Sparta-led Peloponnesian League for dominance over the Greek world, ending nearly a half-century of uneasy peace that had followed the Greco-Persian Wars. The war is chronicled in great detail by the Athenian historian and former general Thucydides, whose unfinished account is prized for its close analysis of political and military decision-making and remains a foundational text of historical and political thought. Fighting ranged across the Greek mainland, Sicily and the Aegean and included the catastrophic failure of Athens's Sicilian Expedition in 415 to 413 BCE, after which Sparta, aided by Persian financial support, gradually gained the upper hand at sea. The war ended in 404 BCE with the surrender of Athens after its fleet was destroyed at the Battle of Aegospotami, stripping Athens of its empire and naval power and leaving the Greek city-states collectively weakened in the decades before Macedonian conquest under Philip II and Alexander the Great.