<P> In the 1050s and early 1060s William became a contender for the throne of England, then held by the childless Edward the Confessor, his first cousin once removed . There were other potential claimants, including the powerful English earl Harold Godwinson, who was named the next king by Edward on the latter's deathbed in January 1066 . William argued that Edward had previously promised the throne to him, and that Harold had sworn to support William's claim . William built a large fleet and invaded England in September 1066, decisively defeating and killing Harold at the Battle of Hastings on 14 October 1066 . After further military efforts William was crowned king on Christmas Day 1066, in London . He made arrangements for the governance of England in early 1067 before returning to Normandy . Several unsuccessful rebellions followed, but by 1075 William's hold on England was mostly secure, allowing him to spend the majority of the rest of his reign on the continent . </P> <P> William's final years were marked by difficulties in his continental domains, troubles with his eldest son, and threatened invasions of England by the Danes . In 1086 William ordered the compilation of the Domesday Book, a survey listing all the landholders in England along with their holdings . William died in September 1087 while leading a campaign in northern France, and was buried in Caen . His reign in England was marked by the construction of castles, the settling of a new Norman nobility on the land, and change in the composition of the English clergy . He did not try to integrate his various domains into one empire, but instead continued to administer each part separately . William's lands were divided after his death: Normandy went to his eldest son, Robert Curthose, and his second surviving son, William Rufus, received England . </P> <P> Norsemen first began raiding in what became Normandy in the late 8th century . Permanent Scandinavian settlement occurred before 911, when Rollo, one of the Viking leaders, and King Charles the Simple of France reached an agreement surrendering the county of Rouen to Rollo . The lands around Rouen became the core of the later duchy of Normandy . Normandy may have been used as a base when Scandinavian attacks on England were renewed at the end of the 10th century, which would have worsened relations between England and Normandy . In an effort to improve matters, King Æthelred the Unready took Emma of Normandy, sister of Duke Richard II, as his second wife in 1002 . </P> <P> Danish raids on England continued, and Æthelred sought help from Richard, taking refuge in Normandy in 1013 when King Swein I of Denmark drove Æthelred and his family from England . Swein's death in 1014 allowed Æthelred to return home, but Swein's son Cnut contested Æthelred's return . Æthelred died unexpectedly in 1016, and Cnut became king of England . Æthelred and Emma's two sons, Edward and Alfred, went into exile in Normandy while their mother, Emma, became Cnut's second wife . </P>

Where did william the conqueror lose two of his sons