Research suggests that this person may never have existed. See the text for details.
Relationships between historical figures could have been simplified or even fabricated in the text to give the impression that succession remained within the same family….Precise chronology is also difficult to assess from the Sagas….The conclusion must be that the tight family network described in the Sagas is unlikely to be correct and that the relationships shown below should be treated with considerable caution. http://fmg.ac/Projects/MedLands/NORWEGIAN%20NOBILITY.htm
ALTERNATE DEATH: 0749 //*Halfdan Sveidasson ... He passed away in 0749. 
Name: Halfdan The Aged /Sveidasson
Name: Halfdan /Sveidasson
Birth: 700: Birth: Oppland, Norway
Death: 770 Oppland, Norway
WikiTree profile Sveidasson-4 created through the import of Lent_Vise_2011-05-11aa.ged on May 26, 2011 by Bryan Sypniewski.
WikiTree profile Sveidasson-17 created through the import of Main Tree_2011-07-30_2011-08-30.ged on Aug 30, 2011 by Sharryn Hopgood.
WikiTree profile Sveidasson-8 created through the import of FAMILY 6162011.GED on Jun 20, 2011 by Michael Stephenson.
The name might be Halfdan Milldi The Meek Ivarsson wife-Hif Dagsdottir. It's possible that this leads eventually to King Halfda Olafsson. I do realize the son is named after fathers first name followed by son and dotter after daughter