In 1066, King Edward the Confessor died.
This resulted in 4 main contenders for the throne.
Harold Godwinson,
Harald Hardrada,
William of Normandy,
And Ethan Ætheling.
The throne was given to Harold Godwinson, then Harald Hardrada attempted to invade England and got killed at the battle of Stamford Bridge.After being delayed by a storm, William of Normandy successfully invaded England after shooting Harold Godwinson in the eye.
He then got renamed to William the conqueror.