Hello, I am looking for information on the parents of Nels O. Boyum who was born on May 20th 1845 near Bergea Norway. He and his son Karl Boyum both went by Olsen / Olson up to sometime between 1900 and 1910. In the 1910 census their name was changed to Boyum. Nels came to Spring Grove Wisconsin in 1870. He married Ragnild Barsness in 1873. Three of five of their children died in infancy. In 1874 he moved to Sherman, SD. Ragnilda died in 1883. He married again in 1888 to Theresa Braa and had four children. Two of which died in infancy. His second wife died in 1897. Married a third time to Beret Brude in 1902. She died in 1912. Also looking to see why they changed their last name.