Thanks for adding that, Regnar.

If i remember right this is the link used by William to claim the throne of England.

Not that I have read.

William would have known that Swein Estrithsson's clais via his mother was far the stronger: as it was the king of Denmark's assumed right - via Hardicnut's deal with king Magnus of Norway, that if either died childless the other would assume possession of his lands and titles: this in fact was the pretext for Harald Hardrada's invasion just before the Norman invasion, because king Harald had assumed Magnus' kingdom upon his death.

William's main claim to the throne of England was his relationship with king Edward (1st cousins once removed), and that Edward had "promised" to make William his heir. Added to those original levers came earl Harold Godwinson's fealty obtained by William; and with it, the oaths of support for William's claim to the throne: this Harold ignored when he took the crown himself.