Ulf Jarl was the son of Danish chieftain
Thorgils Sprakalägg. In the 18th century, Danish historian Jacob Langebek proposed that
Styrbjörn Starke and
Tyra Haraldsdotter were the parents of
Thorkel Sprakalegg. Therefore, this would make Ulf Jarl a descendant of
Olof (II) Björnsson of the
House of Munsö and through Tyra a descendant of
Harald Bluetooth of the
House of Knýtlinga. His brother Eilaf was an earl of King
Cnut the Great and his sister
Gytha Thorkelsdóttir married
Godwin, Earl of Wessex. In 1016, he participated in
Cnut the Great's invasion of England. He participated in the conquest of
England as one of Cnut's most trusted men. From c. 1024 he was appointed the Jarl of Denmark and King Cnut's appointee as regent of Denmark. In the absence of King Cnut, he ruled as the foster-father and guardian of Cnut's son
Harthacnut. In 1026, Swedish King
Anund Jakob and Norwegian King
Olaf II took advantage of King Cnut's absence and launched an attack on the Danish in the Baltic Sea. Ulf convinced the freemen to elect
Harthacnut king, since they were discontented at Cnut's absenteeism. This was a ruse on Ulf's part since his role as Harthacnut's guardian would make him the ruler of Denmark. When Cnut learnt what had happened, he returned to Denmark and fought naval engagement against the Swedish and Norwegian forces at the
Battle of the Helgeå. The victory left Cnut as the dominant leader in Scandinavia. The
Anglo-Saxon Chronicle, which instead places the battle a year earlier in 1025, names the leaders of the Swedes as Ulf and Eglaf, usually identified with Ulf Jarl and his brother Eilaf. Saxo likewise would have Ulf fighting Cnut at Helgeå. However the
Saga of Olaf the Holy in the
Heimskringla gives an account in which Cnut, although having lost the land battle, was the overall victor when Ulf helped him win the accompanying sea battle. One possible explanation for this conflict of sources is that Ulf fought with the Swedes against Cnut in a 1025 battle not recounted by the saga because Olaf did not take part, but Ulf switched sides before the battle at Helgeå. If Eilaf fought against Cnut, he was forgiven as he was retained as Earl in England until Cnut's death, and then fled, suggesting he was closely linked to the king. Any rapprochement with Ulf was short-lived. At a banquet in
Roskilde, the two brothers-in-law were playing
chess and started arguing with each other after Cnut refused to accept the loss of his
knight. The next day, the
Christmas of 1026, Cnut had one of his
housecarls kill Earl Ulf in , the predecessor of
Roskilde Cathedral. ==References==