Siward of Northumbria
He is said to have been of Scandinavian origin (The Life of King Edward says he was called Digri in Danish). He came to England during the reign of Canute the Great, and by 1033 was Earl of Northumbria (which, at that time, extended into modern Yorkshire). He retained the title under Harald Harefoot and, at some point around this timne, he married AElfflaed, daughter of the Earl of Bamburgh. By 1041, the King was Harthacnut, and the Earl of Bamburgh was AElfflaed's uncle, whom Harthacnut "betrayed" (and Siward possibly killed). In the aftermath Swiard became Earl of all Northumbria.
Siward was Earl under Edward the Confessor, and witnessed some of his charters but disappears from these around 1053-55; he is, however, known to have campaigned against Macbeth of Scotland in 1054, losing, in the course, his eldest son and heir, Osbjorn. By 1056 he was in all likelihood dead and in Domesday his lands, in Yorkshire and Derbyshire, are in the hands of Hugh, 1st Earl of Chester.
His other claim to "fame" arises from the biography of his son, Waltheof, who followed him as earl. In this Siward's father is named as Bjorn (Norse for bear), his great-grandfather as Ursus (Latin for bear), who is said to have been the son of a union between a Norse noblewoman and a polar bear.