Theodore Nathanael Mellgren was born on 03 Feb 1889 as the seventh child of John L. Mellgren and Britta Stina Anderson. He had eleven siblings, namely: Anna Charlotte, Algot Levin, Gerhard Vitalis, Anna Victoria, Lydia Eleonora, Florence Eleanor, Adolph Anskarius, Walter Edward, Esther Emelia, Gilbert George, and Clarence Filmore. He died on 29 Apr 1957.