Background
Florence of Worcester named his father as "Ursius" (ie urso, Latin for bear, björn in Scandinavian languages) and Saxo Grammaticus tells the story that this Ursius/Björn was the son of a bear and a fair Swedish maiden.
Florence of Worcester named his father as "Ursius" (ie urso, Latin for bear, björn in Scandinavian languages) and Saxo Grammaticus tells the story that this Ursius/Björn was the son of a bear and a fair Swedish maiden.
In Knýtlinga saga he is also called "the fast". Genealogical speculations of a later date (presumably first suggested by the Danish historians Jakob Langebek and Peter Frederik Suhm) would make Thorgil son of the Viking Styrbjörn the Strong, who in turn is depicted as son of Olaf Björnsson, king of Sweden. Styrbjorn"s wife in the sagas, Thyra, was the daughter of Harold Bluetooth, king of Denmark and Norway.
Number primary source supports this theory and the theory itself is almost impossible to maintain because of the chronological inconsistencies.
Thorgil"s cognomen "Sprakalägg" translated in English means Strut-legal Thorgil"s children were:
Ulf (died 1027), a steward and Earl of Cnut the Great in Denmark, whose son became king Sweyn II of Denmark.
Eilaf (first mentioned 1009), also Earl of King Canute.