In our timeline last King of Saxon England, claimed the throne on the death of Edward the Confessor, defeated his own brother, Tostig Godwinson and Harald Hardråde, King of Norway at the Battle of Stamford Bridge, and then was killed in the Battle of Hastings, against William Duke of Normandy who became William I of England.
- Harold II goes for Duke William first, and the latter is killed or routed (with consequent impacts on Franco-Norman relationships, as William's heir is a child): he is then killed in the battle in the North.
If Tostig alone survived, he would probably succeed to the throne.
If Harald survived he would have united the two realms (and possibly divided them up again much as William I in OTL divided Normandy and England between his sons).
The battles would occur at different locations to OTL.
- Harold alone survives both battles. His position would be secure for the immediate future.
In both Harold II and Tostig on the throne timelines, Edgar the Ætheling, a more direct heir to the throne, but a youth in 1066, would probably have staged an attempt on the throne (much as he was involved in rebellion in OTL).
- All four of Harold, William, Tostig and Hardrada die variously: Edgar (the) Ætheling succeeds to the throne: but possibly faces incursions or interventions from Welsh, Scottish and Scandinavian rulers.
Alternatively William succeeds to the English throne, as in OTL but, during the coronation in Westminster Abbey, the nobles inside the building at one point gave such a shout of acclamation to their new monarch that the Norman soldiers outside thought he was being attacked, and set fire to the building. If this had got out of control much of the leading administration of England would have been killed, and both England and Normandy would have faced a succession crisis (William's sons being children at this time.)