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Background

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 ceding 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, sister of Richard II, Duke of Normandy, as his second wife in 1002.

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.

After Cnut's death in 1035, the English throne fell to Harold Harefoot, his son by his first wife, while Harthacnut, his son by Emma, became king in Denmark. England remained unstable. Alfred returned to England in 1036 to visit his mother and perhaps to challenge Harold as king. One story implicates Earl Godwin of Wessex in Alfred's subsequent death, but others blame Harold. Emma went into exile in Flanders until Harthacnut became king following Harold's death in 1040, and his half-brother Edward followed Harthacnut to England; Edward was proclaimed king after Harthacnut's death in June 1042.