Ælfgifu of Northampton
Aelgifu, also known as, Ælfgifu, Alfgifu, Alfgitha or Elfgifu, (c. 995 - c. 1040) was a daughter of Ælfhelm, Earl of York, who was murdered on the command of Ethelred the Unready, the King of England. She is amongst historians most commonly known as Aelgifu of Northampton, and the 'handfast' wife of Cnut the Great, and the two sons Aelfgifu bore him, Svein of Norway and Harold I, were to figure promintely in the empire which their father built in northern Europe, although sons of Emma of Normandy, King Cnut's court wife, and the twice Queen of England, were also claimants to the throne of her husband.
Cnut sent Aelfgiufu with their eldest son Sweyn to rule Norway, in 1030. Their rule was so harsh though that the Norwegians rebelled against them, and they were driven out, in 1035, while Sweyn died of wounds in Denmark shortly after, probably in 1036. In Norway this period is known as Aelfgifu's Time, remembered for heavy taxes.
Alfgifu was determined that her second son should be the next English king, on the death of Cnut the same year, in 1035. She supposedly bribed the noblemen to accept Harald as a temporary king, or regent, while Harthacnut, Queen Emma's son by the late King of England, was away in Denmark, at war with the Norwegien king Magnus I, and the Swedes under their king Anund Jacob. She was apparently part of a plot to murder Alfred, another son of Queen Emma, by the king Cnut defeated, Ethelred, who was on his way to see his mother after a long exile in Normandy. None could oppose Harald and the English supporters of his claim, especially after his Huscarls laid claim on the treasury, and he was crowned King of England in 1037. Aelfgifu was then to slip into obscurity after his death from an possible stroke, in 1040, and the crowning of Harthacnut, also the King of Denmark and the rightful heir to Cnut.
It of great importance that her age, along with her son's, is entirely based on the evidence which is available on the date of King Cnut's birth, as it is the supposition the couple were the same age, while no definite information survives on the date for marrying of the two. It is maybe the case they were married in 1016, the year before Cnut was to marry his court queen Emma, although it is perhaps even more likely it was in 1004, when Cnut may have been with his father Swegen Forkbeard's raiders, and the infamous Thorkel the High, as they made an attempt on the wealthy city of Norwich. It was a period of extensive Viking attacks throughout England, and the presence of Cnut near the Danelaw, in Northhampton, or even in York, the Earldom of her father, Aelfhelm, is entirely plausible. So... she was at the latest, born in the mid 990s, although an earlier birth in the mid 980s is likely.