http://pilot.familysearch.org/recordsearch/start.html - shows a marriage in 1873 for him, in Branvold, Hedmark, Norway, to Johanne Eleonore Andrea Hagerup
His father is given as Hans Haagensen, hers as Hans Hagerup.
http://www.arkivverket.no/URN:kb_read?idx_kildeid=8880&idx_id=8880&uid=ny&idx_side=-218 - original image shows him as resident in Grimsby.
His christening is listed on that site as "Petter Henrich Haagensen", father Hans mother Andrea nee Boug.
The original image (
http://www.arkivverket.no/URN:kb_read?idx_kildeid=7515&idx_id=7515&uid=ny&idx_side=-21 ) confirms the "August 3" birthdate.
There are also several baptisms for siblings, mostly listed with surname Hansen.
He had at least four sisters - Annette Caroline, 1827, Bergitte Christine, 1830, Maren, 1834, Hanne Jacobine Caroline, 1839
At least one brother, Andreas, b. 1832
His mother remarried in 1841 to Simon Svendsen:
http://www.arkivverket.no/URN:kb_read?idx_kildeid=7515&idx_id=7515&uid=ny&idx_side=-188They had at least two more children: Bergithe Magdalen, 1842, Hanna Andrea, 1846 (as Simonsen/Simonsdatter)
I think this might be his mother with his sister (Bergitte Christine Haagensen m. Hans Carl Funnemark in Moss in 1854) in the 1865 census:
http://www.rhd.uit.no/folketellinger/ftliste_e.aspx?ft=1865&knr=0301&kenr=1857&bnr=1784&lnr=000And probably Maren is here:
http://www.rhd.uit.no/folketellinger/ftliste_e.aspx?ft=1865&knr=0104&kenr=000&bnr=0019&lnr=00Judging from Johanna's address at marriage this is her family:
http://www.rhd.uit.no/folketellinger/ftliste_e.aspx?ft=1865&knr=0421&kenr=004&bnr=0028&lnr=000The boy there, "Frederick Emil", appears to be living with the Haagensen family in 1881 (head of household transcribed as "Postez H. Haagensen", brother in law as "Frederick Hagerun", Frederik Emil Hagerup married in England in 1886).
I can't actually find Peter on the 1865 census, perhaps he was already overseas at that point.