Battle of Welfesholz
1115 CE.
Shown on the map at 51.617°, 11.567°.
The Battle of Welfesholz was fought on 11 February 1115 between the Imperial army of the Emperor Henry V and a rebellious Saxon force led by Lothair of Supplinburg, who would later become the Holy Roman Emperor.
Text from the Wikipedia article Battle of Welfesholz, licensed CC BY-SA 4.0.