Sparta defeated Athens at the Battle of Aegospotami in 405 BCE.
The battle took place near the Hellespont during the final phase of the Peloponnesian War. The Spartan commander Lysander caught the Athenian fleet while many of its crews were ashore. Most of the Athenian ships were captured or destroyed, leaving Athens without the naval power needed to import grain from the Black Sea region.
Aegospotami was strategically more important than its small battlefield location might suggest. The victory allowed Sparta to blockade Athens and cut its essential supply routes. Athens surrendered in 404 BCE, ending the long war between the two leading Greek powers.
The battle is sometimes confused with the final surrender itself. Aegospotami occurred in 405 BCE; Athens capitulated the following year. Lysander’s victory also helped establish Spartan dominance in the Greek world, although that dominance was challenged within a generation.