Wikipedia Biographical Summary:

"...David Hyrum Smith (November 17, 1844 in Nauvoo, Illinois – August 29, 1904, in Elgin, Illinois) was the youngest son of Joseph Smith, Jr. and Emma Hale Smith and, as an adult, was an influential missionary and leader in the Latter Day Saint movement. He was born approximately five months after the murder of his father. Beginning in December 1847, he was raised by his mother and her second husband, Lewis C. Bidamon..."

SOURCE: http://en.wikipedia.org/wiki/David_Hyrum_Smith