On September 28, 1066, Norman forces under the command of William the Conqueror landed in England, beginning the Norman Conquest. Following the death of the English king Edward the Confessor, a dispute over who rightfully held claim to the throne arose due to a lack of a clear heir. Harold Godwinson, Earl of Wessex, became Edward's immediate successor; however, Duke William II of Normandy claimed that the throne was promised to him by Edward and the Norwegian king Harald Hardrada claimed it was his due to a previous agreement between his predecessor and a previous English king.

Harald Hardrada led an invasion of northern England in early September and were initially victorious in battle. However, Harold soon intercepted the force and, taking them by surprise, slaughtered them at the Battle of Stamford Bridge. Of an estimated strength of 9,000 men, nearly 6,000 Norwegians lay dead at the end of the battle, including the Norwegian king himself. While Harold had successfully ended the Norwegian invasion, his fortune was to be short-lived as William II and Norman army lands in southern England within days.

Harold advanced south to deal with the Norman threat, but he left much of his army in the north to handle the Norwegians. Meanwhile, William had set up defensive positions and began raiding the surround lands at Pevensey Bay. On October 14, the English and Norman armies met at the Battle of Hastings, where Harold was killed. On December 25, William succeeded in securing the English throne, though he was still forced to contend with a number of insurrections and rebellions for the rest of his reign.