http://en.wikipedia.org/wiki/Agatha,_wife_of_Edward_the_Exile

Agatha was the wife of Edward the Exile and mother of Edgar Ætheling, Saint Margaret of Scotland and Cristina of England. Her antecedents are unclear, and subject to much speculation.
Nothing is known of her early life, and what speculation has appeared is inextricably linked to the contentious issue of Agatha's paternity, one of the unresolved questions of medieval genealogy. She came to England with her husband and children in 1057, but she was widowed within weeks of arriving. Following the Norman conquest of England, in 1067 she fled with her children to Scotland, finding refuge under her future son-in-law Malcolm III. While one modern source indicates that she spent her last years as a nun at Newcastle-upon-Tyne, dying before circa 1093 [1], Simeon of Durham [1] carries what appears to be the last reference to her in 1070.[2]