Battle of Lincoln
1141 CE.
Shown on the map at 53.235°, -0.555°.
The Battle of Lincoln, or the First Battle of Lincoln, occurred on 2 February 1141 in Lincoln, England between King Stephen of England and forces loyal to Empress Matilda. Stephen was captured during the battle, imprisoned, and effectively deposed while Matilda ruled for a short time.
Text from the Wikipedia article Battle of Lincoln (1141), licensed CC BY-SA 4.0.