Battle of Tinchebray
1106 CE.
Shown on the map at 48.765°, -0.728°.
The Battle of Tinchebray (alternative spellings: Tinchebrai or Tenchebrai) took place on 28 September 1106, in Tinchebray (today in the Orne département of France), Normandy, between an invading force led by King Henry I of England, and the Norman army of his elder brother Robert Curthose, the Duke of Normandy. Henry's knights won a decisive victory: they captured Robert, and Henry imprisoned him in England (in Devizes Castle) and then in Wales until Robert's death (in Cardiff Castle) in 1134.
Text from the Wikipedia article Battle of Tinchebray, licensed CC BY-SA 4.0.