Estrid Bjørnsdotter was the daughter of Björn Byrdasvend and Rangrid Guttormsdotter, who was a probable descendant of Tostig Godwinson, the brother of the last Anglo-Saxon King of England Harold Godwinson.
Some of the earliest surviving documents to mention the word Scotland include the Anglo-Saxon Chronicles of Abingdon, Worcester and Laud, written during the 11th Century, which state that prior to the Battle of Stamford Bridge in 1066, Earl Tostig had sought refuge in Scotland under the protection of Malcolm III, King of Scots.
The house of Mathrafal was effectively established in the wake of Harold and Tostig Godwinson's disastrous raids in 1062 and 1063.
These were subsequently taken from the monastery by Earl Godwin for his fourth son, Tostig.
Following the 1063 invasion of Wales by Harold and Tostig Godwinson that overthrew Gruffydd, Rhiwallon and Bleddyn jointly received Powys and Gwynedd on condition of faithfully serving Edward the Confessor "everywhere by water and by land".
Craven in the Domesday Book shows that up till 1066 Earl Tostig was lord of Grindleton and the surrounding areas of West Bradford, Waddington, Bashall Eaves, Great Mitton, Hammerton, Slaidburn, Dunnow, Newton, Bogeuurde, Easington, Radholme Laund and Lees.