Holmfrid, syster till Olof Skötkonung, gift med Svein Håkonsson.

http://sv.wikipedia.org/wiki/Olof_Sk%C3%B6tkonung

From the Foundation for Medieval Genealogy page on Sweden:

http://fmg.ac/Projects/MedLands/SWEDEN.htm

[HOLMFRID.

Snorre records the betrothal of "Svein, a son of Earl Hakon, and Earl Eirik's brother" and "Holmfrid, a daughter of King Olaf the Swedish king", although it is chronologically more probable that she was the sister rather than daughter of King Olav[37]. If this is correct, it is not certain that Sigrid was her mother.

m SVEN Haakonsson Ladejarl of Norway, son of Jarl HAAKON Sigurdsson "the Mighty" & his wife Thora Skagadatter (-1016).]

From the Foundation for Medieval Genealogy page on Norway Nobility:

http://fmg.ac/Projects/MedLands/NORWEGIAN%20NOBILITY.htm#SvenHaakonssondied1016

Sven Haakonsson m HOLMFRID, daughter of [ERIK "Segersäll/the Victorious" King of Sweden] & [his wife Sigrid "Storråda/the Haughty"].

Snorre records the betrothal of "Svein, a son of Earl Hakon, and Earl Eirik's brother" and "Holmfrid, a daughter of King Olaf the Swedish king", although it is chronologically more probable that she was the sister rather than daughter of King Olav[95].

Sven & his wife had two children:

1. Sigrid Svensdatter (married Aslak Erlingsson)

2. Gunhild Svensdatter (d. after 1060, married firstly, Anund Jakob, King of Sweden, her first cousin, secondly after the church-mandated annulment Svend II King of Denmark)

From the Swedish-language Historiska Personer i Sverige och Norden page on Holmfrid (Helmfrid) Eriksdotter:

http://historiska-personer.nu/min-s/p02d3e156.html

Holmfrid (Helmfrid) Eriksdotter

Far: Erik >> Segersäll (945 - 995)

Mor: Sigrid Storråda (- 1000)

Noteringar

Snorre Sturlasson skriver att Holmfrid (även namnet Helmfrid förekommer i källorna) var dotter till Olof Skötkonung och inte syster till honom. Andra källor påstår att hon var syster till Olof. Kombineras detta med att det kronologiskt var omöjligt att hon var Olofs dotter, kan slutsatsen dragas, att Snorre hade fel.

(Källa: Brian Tompsett, University of Hull, England)

In English:

Holmfrid (Helmfrid) Eriksdotter

Father: Eric the Victorious (945-995)

Mother: Sigrid (d. 1000)

Family with Sven of Norway (Hakansson)

Married: 996

Children:

1. Sigrid Hakansdotter

2. Gunhild Hakansdotter

Entries:

Snorre Sturluson wrote that Holmfrid (also called Helmfrid in sources) was the daughter of Olof and not his sister. Other sources claim that she was the sister of Olof. Combine this with the chronological impossibility that she was daughter of Olof and the conclusion can be drawn that Snorre was wrong.

(Source: Brian Tompsett, University of Hull, England)