Battle of Delium
423 BCE.
Shown on the map at 38.348°, 23.649°.
The Battle of Delium (or Delion, a city in Boeotia) took place in 424 BC, during the Peloponnesian War. It was fought between the Athenians and the Boeotians, who were allies of the Spartans, and ended with the siege of Delium in the following weeks.
Text from the Wikipedia article Battle of Delium, licensed CC BY-SA 4.0.