Chronicler Adam of Bremen says that Harthacnut came from Northmannia to Denmark and seized power in the early 10th century.

[7] His wife, Thyra, is credited with the completion of the Danevirke, a wall between Denmark's southern border and its unfriendly Saxon neighbours to the south.

[9] Arild Huitfeldt relates one legend of his death in Danmarks Riges Krønike:[8] The three sons were Vikings in the truest sense, departing Denmark each summer to raid and pillage.

Harald came back to the royal enclosure at Jelling with the news that his brother Canute had been killed in an attempt to capture Dublin, Ireland.

Queen Thyra ordered the royal hall hung with black cloth and that no one was to say a single word.

Gorm understood immediately the Queen's metaphor and cried out, "My son is surely dead, since all of Denmark mourns!"

Saxo Grammaticus in the Gesta Danorum asserts that Gorm was older than other monarchs and, having lived so long, was blind by the time his son Canute was killed.