Battle of Bibracte
57 BCE.
Shown on the map at 46.917°, 4.033°.
The Battle of Bibracte was fought between a Gallic confederation centred around the Helvetii and a Roman army under the command of Gaius Julius Caesar. It was the first major battle of the Gallic Wars.
Text from the Wikipedia article Battle of Bibracte, licensed CC BY-SA 4.0.