Ulf the Earl

Ulf (or Ulf Jarl) was a Danish earl (jarl). As a Viking chieftain he participated in Cnut the Great's conquest of England as one of his most trusted men. He married Cnut's sister Estrid Svendsdatter and from c. 1024 he was his appointee as regent of Denmark, probably as the guardian of Cnut's young son Harthacnut. After Ulf joined Olaf II of Norway and Anund Jacob of Sweden in a coalition against Cnut, Cnut had him killed in Roskilde. He was the father of Sweyn II of Denmark, King of Denmark from 1047 to 1074.

Biography
Ulf Jarl was the son of Thorgils Sprakalägg, who is claimed to have been the son of Styrbjörn the Strong, a scion of the Swedish royal house, by Tyra, the daughter of king Harald Bluetooth of Denmark. However, Thorgils' parentage may have been invented to glorify the royal dynasty founded by Ulf's son, Sweyn Estridson.

Ulf joined Cnut the Great's expedition to England. In c. 1015, he married Cnut's sister Estrid and was appointed the Jarl of Denmark, which he ruled when Cnut was absent. He was also the foster-father of Cnut's son Harthacnut.

When the Swedish king Anund Jakob and the Norwegian king Olaf II took advantage of Cnut's absence and attacked Denmark, 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 in 1026, he returned to Denmark and with Earl Ulf's help, defeated the Swedes and the Norwegians at the Battle of the Helgeå. Ulf's assistance did not, however, cause Cnut to forgive Ulf for his coup. At a banquet in Roskilde, the two brothers-in-law were playing chess and started arguing with each other. The next day, the Christmas of 1026, Cnut had one of his housecarls kill Earl Ulf in Trinity Church, the predecessor of Roskilde Cathedral. However, accounts contradict each other.

Ulf was the father of Sweyn Estridson, and thus the progenitor of the House of Estridsen, which would rule Denmark from 1047 to 1375, which was also sometimes, specially in Swedish sources, referred to as the Ulfinger dynasty to honor him.