Internal Wars from the “First Peloponnesian War” to Chaeronea

Thucydides' terse narrative is tendentious, however, and deliberately shaped to support his contention that the "truest cause" of the Peloponnesian War was the growth of Athenian power and the fear it engendered in the Spartans. In the opening engagement, the Athenians attempted to counter Corinthian ambitions in the eastern Peloponnese by attacking the port town of Halieis on the Argolic gulf, where they were defeated in a land battle by the Corinthians, Epidaurians, and Sicyonians. The outbreak of the Peloponnesian War occurred in the spring of 431, when the Thebans attempted to invade the recalcitrant Boeotian city of Plataea, a loyal ally of Athens. The generation‐long Peloponnesian War resulted in the collapse of the polarization between Athens and Sparta and left a lasting legacy on Greece. The combined armies of the Athenians and the Thebans attempted to bar Philip's passage south in 338 at Chaeronea in Boeotia.