Ancestors of Henry II (Plantagenet) King of England, Url: @ "a sister of Siward Earl of Northumbria"
The cited information was published by 15 Nov 1995 (Ref: "a sister of Siward Earl of Northumbria") The author/originator was Douglas McMartin.
Source Notes
TITL Ancestors of Henry II (Plantagenet) King of England, Url:
http://intermid.com/DoutBerg/genealog.y/royhenry.htmABBR Henry II Plantagenet website