Siege of Thessalonica
254 CE.
Shown on the map at 40.633°, 22.950°.
The siege of Thessalonica in 254 was a successful defense of the city of Thessalonica by local Roman militia during an invasion of the Balkans by the Goths.
Text from the Wikipedia article Siege of Thessalonica (254), licensed CC BY-SA 4.0.