What marked the end of the Peloponnesian War?

The conclusion of the Peloponnesian War is predominantly marked by the Spartan victory at Aegospotami in 405 BCE. This pivotal naval battle took place near the Hellespont, where the Spartan fleet, commanded by Lysander, decisively defeated the Athenian naval forces. This defeat crippled Athenian power and effectively ended its dominance at sea.

Following the victory at Aegospotami, Athens was unable to sustain its war efforts, leading to its eventual surrender in 404 BCE. This victory not only dismantled the Athenian fleet but also ensured Spartan control over the seas, which was crucial for maintaining their military strategy against Athens.

While the destruction of the Athenian navy and the subsequent formation of a peace treaty were significant events, the immediate military action and decisive nature of the battle at Aegospotami were what directly precipitated the end of the conflict. The death of key leaders, while impactful, did not serve as a definitive endpoint within the broader context of the war's conclusion.