Harald III of Norway and his English ally Tostig Godwinson defeated the northern earls Edwin and Morcar at the Battle of Fulford near York.

Harald Sigurdsson, also known as Harald III of Norway and given the epithet Hardrada in the sagas, was King of Norway from 1046 to 1066. He unsuccessfully claimed the Danish throne until 1064 and the English throne in 1066. Before becoming king, Harald spent 15 years in exile as a mercenary and military commander in Kievan Rus' and chief of the Varangian Guard in the Byzantine Empire. In his chronicle, Adam of Bremen called him the "Thunderbolt of the North".

Tostig Godwinson was an Anglo-Saxon Earl of Northumbria and brother of King Harold Godwinson. After being exiled by his brother, Tostig supported the Norwegian king Harald Hardrada's invasion of England, and was killed alongside Hardrada at the Battle of Stamford Bridge in 1066.

Edwin was the elder brother of Morcar, Earl of Northumbria, son of Ælfgār, Earl of Mercia and grandson of Leofric, Earl of Mercia. He succeeded to his father's title and responsibilities on Ælfgār's death in 1062. He appears as Earl Edwin in the Domesday Book.

Morcar was the son of Ælfgār and brother of Ēadwine. He was the earl of Northumbria from 1065 to 1066, when William the Conqueror replaced him with Copsi.

The Battle of Fulford was fought on the outskirts of the village of Fulford, just south of York in England, on 20 September 1066, when King Harald III of Norway, also known as Harald Hardrada, a claimant to the English throne and Tostig Godwinson, his English ally, fought and defeated the Northern Earls Edwin and Morcar.