Ragnarssona þáttr states that when his father died, Sigurd inherited
Zealand,
Scania,
Halland, the Danish islands, and
Viken. It is also possible he was for a time co-ruler of Denmark with his brother Halfdan, because Frankish sources mention certain
Sigfred and Halfdan as rulers in 873 – the names Sigurd and Sigfred were often mixed up in Nordic literature. He could have succeeded his brother
Halfdan Ragnarsson as the sole king of Denmark in about 877, when Halfdan fell in battle in the
Irish Sea. A Danish Viking king called Sigfred, who appears to have become landless by this time, was killed in
West Francia in 887; he is quite possibly the same person. Sigurd married Blaeja, the daughter of king Ælla of Northumbria and they had two children,
Harthacanute and Áslaug Sigurðardóttir, who was married to
Helge of the
Dagling lineage. Helge may have briefly succeeded his purported father-in-law as king of Denmark before being overthrown by
Olof, a Viking chief who swept down from Sweden in about the year 900. The
Ragnarssona þáttr states that Danish king
Harthacanute was a son of Sigurd. However, the 11th century chronicler
Adam of Bremen mentions Hardegon (probably Harthacanute) as the son of a certain Sven. Hardegon or Harthacanute succeeded
Sigtrygg Gnupasson as the king of part of Denmark (probably
Jutland, but according to later tradition
Zealand,
Scania and
Halland) in about 916. According to the
Ragnarssona þáttr, he nevertheless lost Viken (
Oslofjord) that had been part of the Danish realm in the 9th century. He was the father of
Gorm the Old, the king of Denmark. Gorm succeeded his father as king and married
Thyra. Gorm's son,
Harald Bluetooth succeeded his father as king and married possibly three times with Gunhild,
Tove and
Gyrid. Harald had a son named
Sweyn Forkbeard. Sweyn succeeded his father as king and married Gunhild (
Świętosława of
Poland). They had a son named
Cnut the Great. Sweyn also ruled England in his lifetime and established the Danish Empire. When Sweyn died, his elder son
Harald Svendsen became the king of Denmark, while England's former king,
Ethelred, reclaimed the throne. Following Harald's death, his brother Cnut the Great became king, re-established the Danish North Sea Empire. He married
Emma of Normandy with whom he had a son named
Harthacnut. When Cnut died (and after the brothers of Harthacnut also had died), Harthacnut became king of Denmark and England. Upon his death,
Edward the Confessor became ruler of England in 1042. Sweyn Forkbeard also had a daughter,
Estrid, from whom all ruling kings and queens of Denmark after 1047 descend. Sigurd's daughter Áslaug, as mentioned above, married
Helgi the Sharp of the
Dagling dynasty. They had a son named
Sigurd Hart, who married a woman named Ingeborg. Sigurd Hart and Ingeborg had children named Guttorm Sigurdsson and Ragnhild Sigurdsdotter. When Sigurd Hart's uncle, king Fróði of
Ringerike died, Sigurd Hart supposedly went to Norway to succeed him as king of Ringerike. == Popular culture ==