 Although the campaigns were successful, he was never able to conquer Denmark.Not long after Harald had renounced his claim to Denmark, the former Earl of Northumbria, Tostig Godwinson, brother of the newly chosen (but reigning not for long) English king Harold Godwinson (also known as Harold of Wessex), pledged his allegiance to Harald and invited him to claim the English throne.Harald went along and invaded Northern England with 10,000 troops and 300 longships in September 1066, raided the coast and defeated English regional forces of Northumbria and Mercia in the Battle of Fulford near York.