Aethelred had first married Aelfgifu then in 1002 he married Emma the daughter of Richard I Duke of Normandy. Aethelred hoped that by marrying into Emma's family they could provide assistance against the Vikings. Aethelred also had many Danes living in England murdered in order to prevent them assisting the invading Vikings. This events is known as the Massacre of St Brice's day. Finally, in 1013, the Vikings invaded England forcing Aethelred and his family into exile in Normandy.
From September of 1013 until his death in February 1014, Swein Fork-Beard of Denmark is acknowledged as King of all England. After Swein's death his son Canute was elected King of England by the Danes but the Witan council elected Aethelred and wanted his reinstatement. Aethelred sent a delegation from Normandy, including his son Edward (the Confessor), to England to discuss his return. Canute returned to Denmark to enforce his control there and in March of 1014 Aethelred returned to England to resume his reign. Canute had not given up his fight for control of England and in April 1016 he returned to England to overthrow Aethelred but the Saxon King died in the same month. Edmund Ironside, Aethelred's eldest son, was chosen to be king by the Londoners but elsewhere others chose Canute.