England’s childless Anglo-Saxon king, Edward, called the Confessor, on his deathbed in the first days of January 1066, allegedly names Harold Godwinson, Earl of Wessex, heir to the English throne; he dies on January 4 or 5.

In any case, the Witenagemot, gathering at Thorney Island where Edward's Westminster Abbey had been dedicated days before he died, proclaims Harold, the richest and most powerful of the English aristocrats, King of England.

He is crowned as Harold II on January 6, by Ealdred, Archbishop of York, probably in the new Westminster Abbey, although Norman propaganda will claim the ceremony had been performed by Stigand, the uncanonically elected Archbishop of Canterbury.

Later in the month, Harold marries Ealdgyth, daughter of the late Earl Ælfgar, and widow of Welsh ruler Gruffydd ap Llywelyn.

Harold is at once challenged by two powerful neighboring rulers.

Duke William of Normandy claims that he had been promised the throne by King Edward and that Harold had sworn agreement to this.

Harald III of Norway, commonly known as Harald Hardrada, also contests the succession.

His claim to the throne is based on an agreement between his predecessor Magnus I of Norway, and the earlier King of England Harthacanute, whereby if either died without heir the other would inherit both England and Norway.

William and Harald immediately set about assembling troops and ships for separate invasions.