The Siege Plataea: Athens vs Sparta The Siege of Plataea (429–427 BC) was a crucial conflict during the protracted Peloponnesian War between Athens and Sparta. Plataea, a small city-state in Boeotia, was an ally of Athens and a strategic location due to its proximity to Thebes, a Spartan ally. In 429 BC, following the outbreak of war, Sparta sought to subdue Plataea, believing its fall would weaken Athenian power. Spartan forces besieged the city, cutting off supplies and attempting to starve th