Born between 1 January 1925 and 31 December 1950
If you were born between 1 January 1925 and 31 December 1950, you became Norwegian at birth if your father was Norwegian when you were born and he was married to your mother.
You also became Norwegian at birth if your mother was Norwegian when you were born, but not married.
Documentation
You must have a birth certificate and be able to document that at least one of your parents was Norwegian when you were born.
If your father or if both your parents were Norwegian you must submit your parents’ marriage certificate.
If only your mother was Norwegian you must submit documentation that shows that your parents were not married when you were born.
Applicable law
"The Norwegian Nationality Act of 8 August 1924, no 3".