Battle of Haliartus
394 BCE.
Shown on the map at 38.379°, 23.088°.
The Battle of Haliartus was fought in 395 BC between Sparta and Athens. After the Athenian defeat at the Peloponnesian War, Athens tried to recover, but also gained the support of Boeotia. Dissatisfied with this situation, Sparta sent an army against Athens and was defeated by the Athenians and Boeotians. Lysander, one of Sparta's most successful generals, was killed in this battle. Haliartus marked the start of the Corinthian War, which continued until 387 BC.
Text from the Wikipedia article Battle of Haliartus, licensed CC BY-SA 4.0.