When Sigrid Undset was two years old the family moved to Kristiania.
Sigrid Undset had two sisters: Ragnhild born in 1884 and Signe Dorothea born in 1887.
In 1909 Sigrid Undset met the painter Anders Castus Svarstad in Rome. He was married and the father of three children, Ebba, Gunhild and Trond.
Sigrid Undset and Anders Castus Svarstad were married at the consulate in Antwerp on the 30th of June 1912.
They had three children:
Anders Castus Svarstad jr. (1913 – 1940)
Maren Charlotte, called Mosse, (1915 – 1939)
Hans Benedict Hugh (1919 – 1978)
Sigrid Undset became preoccupied with the catholic church in 1924 and the marriage to Anders Castus Svarstad was dissolved. Sigrid Undset died on the 10th of June 1949 in Lillehammer and is buried in the churchyard at Mesnalia.