Harold "Klak", King of Haithabu, King of Rustringen, 819-827, King of Jutland. His wife, Elgina, was a daughter of Æthelred (Ethelred) I, King of Wessex.
[S2993] Stuart, Roderick W, Stuart-2002, (Genealogical Publishing Co: 2002 4th Edition), p 118 (Troverdighet: 3).
Shows Harald Klak's father as Halfdan - skipping a generation shown in other sources.