Birthdate estimated using the Fahlun Lutheran Church parish funeral records, which stated his age at death was 67 years, 4 days old.

Very possibly his marriage, based on the 1900 census info:

DOUGLAS A - 163 11/26/1870
PETERSON, OLOF
OLESON, MARTINA

Ole Peterson
United States Census, 1880
Name Ole Peterson
Event Type Census
Event Date 1880
Event Place Belle River, Douglas, Minnesota, United States
Gender Male
Age 35
Marital Status Married
Race White
Race (Original) W
Occupation Farmer
Relationship to Head of Household Self
Relationship to Head of Household (Original) Self
Birth Year (Estimated) 1845
Birthplace Sweden
Father's Birthplace Sweden
Mother's Birthplace Sweden
Sheet Letter C
Sheet Number 446
Person Number 0
Volume 1
1880
Household
Ole Peterson Self M 35 Sweden
Martha Peterson Wife F 35 Sweden
Peter Peterson Son M 10 Minnesota, United States
Christina Peterson Daughter F 8 Minnesota, United States
John Peterson Son M 5 Minnesota, United States
Carl Peterson Son M 1 Minnesota, United States
Citing this Record
"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MZ9Q-Q9D

Ole Peterson
United States Census, 1900
Name Ole Peterson
Event Type Census
Event Year 1900
Event Place Alexandria Township (excl. Alexandria village), Douglas, Minnesota, United States
Gender Male
Age 53
Marital Status Married
Race White
Race (Original) W
Relationship to Head of Household Head
Relationship to Head of Household (Original) Head
Years Married 30
Birth Date Sep 1847
Birthplace Sweden
Marriage Year (Estimated) 1870
Immigration Year 1866
Father's Birthplace Sweden
Mother's Birthplace Sweden

HOUSEHOLD
Ole Peterson Head M 53 Sweden
Martha Peterson Wife F 56 Sweden
John Peterson Son M 25 Minnesota
Carl Peterson Son M 21 Minnesota
Tillie Peterson Daughter F 16 Minnesota

1905 Census - in Alexandria township.
Ole Petterson Male 59 White Sweden 1846 Sweden Sweden
Martina Petterson Female 61 White 1844 Sweden Sweden
Tilda Petterson Female 21 White 1884 Sweden Sweden

Ole Peterson
United States Census, 1910
Name Ole Peterson
Event Type Census
Event Date 1910
Event Place Alexandria, Douglas, Minnesota, United States
Gender Male
Age 63
Marital Status Married
Race White
Race (Original) White
Relationship to Head of Household Head
Relationship to Head of Household (Original) Head
Birth Year (Estimated) 1847
Birthplace Sweden
Immigration Year 1866
Father's Birthplace Sweden
Mother's Birthplace Sweden
Sheet Letter A
Sheet Number 1

HOUSEHOLD
Ole Peterson Head M 63 Sweden
Martina Peterson Wife F 66 Sweden

Martina or Martha's information on the 1900 census:
Martha Peterson
United States Census, 1900
Name Martha Peterson
Event Type Census
Event Year 1900
Event Place Alexandria Township (excl. Alexandria village), Douglas, Minnesota, United States
Gender Female
Age 56
Marital Status Married
Race White
Race (Original) W
Relationship to Head of Household Wife
Relationship to Head of Household (Original) Wife
Number of Living Children 6
Years Married 30
Birth Date May 1844
Birthplace Sweden
Marriage Year (Estimated) 1870
Immigration Year 1867
Father's Birthplace Sweden
Mother's Birthplace Sweden
Mother of how many children 6