The Evanger Boka has Rasmus married about 1672, wife not known. The first child, Haldor, was born 1667, 5 years before the marriage. By tradition, Haldor, being the first born, should have inherited the farm, but he didn't. The second son Johannes, born 1672, inherited the farm, which leads me to believe that the woman Rasmus married was probably a widow, with a five year old son. I would think that if Haldor was the son of Rasmus, though the marriage was long delayed, he would have inherited the farm.

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http://www.fadness.com/10_rasmus_nilsson_tyssen.htm