Peter Nilsson was born on the Bjørndalen farm, Sigdal parish, on January 22, 1838 to parents "selveier" (owner or freeholder) Nils Kristoffersson and Hella Petersdotter Bjørndalsplassen.
He was baptized March 4, 1838 in Sigdal parish and was also baptized at home on January 22, 1838 by his aunt Kari Kristoffersdotter Tingelstad "eie".
