Battle of Cynwit
878 CE.
Shown on the map at 51.159°, -3.078°.
The Battle of Cynwit or Countisbury Hill took place between West Saxons and Vikings in 878. The location of the fortress the battle is named for is not known with certainty but probably was at Countisbury Hill or Wind Hill, near Countisbury, Devon. A possible alternative site for the siege and battle is Cannington Camp in the Parrett estuary near Combwich.
Text from the Wikipedia article Battle of Cynwit, licensed CC BY-SA 4.0.