Battle of Mantinea
417 BCE.
Shown on the map at 37.600°, 22.400°.
The first Battle of Mantinea was fought in 418 BC during the Peloponnesian War. In this battle, Sparta and its Peloponnesian allies defeated an allied army of Argos, Athens, Mantinea and several others.
Text from the Wikipedia article Battle of Mantinea (418 BC), licensed CC BY-SA 4.0.