Battle of Thermopylae (254)
254 CE.
Shown on the map at 38.805°, 22.563°.
The Battle of Thermopylae in 254 was a successful defense of the pass of Thermopylae by local Greek militia under Marianus, the Roman proconsul of Achaea, during an invasion of the Balkans by the Goths.
Text from the Wikipedia article Battle of Thermopylae (254), licensed CC BY-SA 4.0.