Knut Olav Strætkvern is trying to see if he can find if Martin is indeed the male line ancestor of the two Ellefsens who carry the R-S7293 (Powys) SNP.

We cannot find any e-mail information for these Ellefsens on FamilyTreeDNA.  They had joined a FTDNA Project group for the study of the Schjelderup family but no e-mail is given for the administrator of this Project group: it has probably collapsed.  In England I would painstakingly go through the English birth, marriage and death records and all censuses open to the public and I might well be able to find them.  But I do not know the Norwegian records, though Knut refers to them as good.  And I have no Norwegian.

I have hope that we will eventually find who these Ellefsens are and whether they are descendants of this Martin.

The problem could be that this Martin or his sons changed their name and used this to conceal their birth name or they caused an NPE in another family.  If either of these happened these two Ellefsens would have no idea of their true male-line ancestry as shown by their Terminal SNP being a sub-set of the Terminal SNP held by at least one modern-day Powys of England.

If anyone reads this and knows anything to help resolve this, please get in touch with me soonest on <tim@powys.org>.
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His baptism from FamilySearch:

Name:           Martin Halvorsen
Event Type:     Christening
Event Date:     12 Oct 1856
Event Place:    Aamot, Hedmark, Norway
Gender:         Male
Birth Date:     30 Jul 1856
Father's Name:  Halvor Powys
Mother's Name:  Oline Eriksdr
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This is the only baptism of a son of Martin Halvorsen after he was in the 1875 census until 1925:

This baptism of an apparent son and an alternative account give tempting suggestions, also from FamilySearch:

Name:           Thorvald Helmer Martinsen
Event Type:     Christening
Event Date:     15 Apr 1894
Event Place:    Risør, Aust-Agder, Norway
Gender:         Male
Birth Date:     18 Mar 1894
Father's Name:  Martin Halvorsen
Mother's Name:  Torine Marie Thorsdr

These look like the same baptism but with the son given the same surname as his father:

Name:           Thorvald Helmer Halvorssen
Event Type:     Christening
Event Date:     15 Apr 1894
Event Place:    Austre Moland, Aust-Agder, Norway
Gender:         Male
Birth Date:     18 Mar 1894
Father's Name:  Martin Halvorssen
Mother's Name:  Thorin Marie Thorsdr

And, presumably from the second parish register:
Name:           Torvald Helmer Halvorsen
Event Type:     Christening
Event Date:     15 Apr 1894
Event Place:    Barbu, Aust-Agder, Norway
Gender:         Male
Birth Date:     18 Mar 1894
Father's Name:  Martin Halvorsen
Mother's Name:  Marie Thorsen
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I can find no marriage record for him, though there are plenty of other Martin Halvorsen marriages.
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Now to see if Thorvald was the father on any baptism:

But none found on FamilySearch from 1914 to 1950.
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A few Ellefsens have been found in theearly 20th century but not may and there may be some filtering out of living Ellefsens.
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