Final answer:
The succession crisis in 1066 was caused by the lack of a clear heir after King Edward the Confessor's death, leading to multiple claimants and culminating in William of Normandy's victory at the Battle of Hastings.
Step-by-step explanation:
The succession crisis in 1066 arose from the lack of a clear heir to the English throne after the death of Edward the Confessor. Immediately following his death, there were several claimants to the throne, creating a power vacuum that led to a series of conflicts. One of the most prominent figures was Harold Godwinson, who was elected king by the Witan (English council of nobles), even though he may not have been the deceased king's first choice.
William, Duke of Normandy, claimed that Edward had promised him the throne, and he had seemingly secured an oath from Harold to support his claim prior to Edward's death. Additionally, there was Harald Hardrada of Norway, who argued that his claim was based on an earlier agreement between the previous kings of England and Norway. The crisis led to the fateful Battle of Hastings in which William defeated Harold, effectively ending Anglo-Saxon rule and leading to Norman control of England.