The Battle of Hastings, 1066
A Walden ancestor was on each side.
William the Conqueror
and
Harald III Sigurdsson - 'Hardrada'
Probably the most famous battle in English history, in 1066, this battle was the last successful invasion of England. William the Conqueror, Duke of Normandy, defeated the Saxon army, and killed the king, Harold III Sigurdsson (1015 - 1066), the last great Viking and the most feared warrior of his world and time.
Atoning for the bloodshed: William the Conqueror and the Foundation of Battle Abbey, n.d., Historic England. https://www.english-heritage.org.uk/visit/places/1066-battle-of-hastings-abbey-and-battlefield/history-and-stories/the-foundation-of-battle-abbey/