Joseph Smith, Jr. (1805 - 1844) was the founder and 1st President of the Church of Jesus Christ of Latter-day Saints. Joseph Smith was the first prophet, seer and revelator of the church. Joseph was born on December 23, 1805 in Sharon, Vermont.
After hearing the conflicting claims of different Protestant preachers, Smith studied the Bible for himself. He decided to ask God which church he should join. In the Spring of 1820, Joseph said that he saw two beings, God (meaning the Father) and Jesus, in a vision. Smith claimed to have been repeatedly visited by an angel named Moroni, from 1823 to 1827. According to Smith's account, Moroni showed him where to find buried gold plates. The plates were said to contain the full gospel of Jesus Christ in "reformed Egyptian" (a language which few, if any non-Mormon, believes ever existed). Smith claimed to have translated these gold plates by the inspiration of God, using a set of unusual spectacles that were also furnished to him for the purpose. He published the translation in 1830 as the Book of Mormon. The plates are not available for examination because, according to Smith, the angel took them after the translation was completed. One of Smith's earliest followers and co-workers had previously worked in a publishing office where he may have had access to the manuscript of a novel that told the story of lost tribes in America.
It was claimed that, on May 15, 1829, the resurrected John the Baptist appeared to Joseph and Oliver Cowdery and gave them the authority to baptize. In 1829 the apostles Peter, James, and John gave them the authority to restore Christ's Church.
Smith married Emma Hale (daughter of Isaac Hale) in 1827 against her father's wishes. A judge in South Bainbridge, New York married them. This angered her father, who said to Smith “You have stolen my daughter and married her. I had much rather have followed her to the grave.” 
Later, in Nauvoo, Joseph Smith founded an impressive militia, announced his intention to run for President of the United States, and tried to establish polygamy. Between 1841 and 1843, Joseph married more than thirty wives although he kept the practice hidden from the public and from Emma. In order to cause Emma to accept his additional wives, Joseph claimed to receive a revelation regarding this “new and everlasting covenant” of plural marriage, partly directed at Emma - Doctrine and Covenants 132:
D&C 132:1 Verily, thus saith the Lord...
D&C 132:4 ...no one can reject this covenant and be permitted to enter into my glory.
D&C 132:52 And let mine handmaid, Emma Smith, receive all those [wives] that have been given unto my servant Joseph...
D&C 132:55 But if she will not abide this commandment, then...I will...give unto him an hundred fold in this world, of...wives...”
D&C 132:62 And if he have ten virgins given unto him...he cannot commit adultery...
D&C 132:64 ...if any man have a wife...and he teaches unto her [this] law...then shall she believe and administer unto him, or she shall be destroyed...
Despite the document's stipulation that the multiple wives be "virgins", Smith unabashedly married eleven women who had current marriages to other men (who were still alive at the time of each woman's marriage to Smith).
Smith's wives (and their husbands) were: Emma Hale, Fanny Alger (16 years old), Lucinda Morgan Harris (married to George W Harris), Louisa Beaman, Zina Huntington Jacobs (married to Henry Jacobs), Presendia Huntington Buell (married to Norman Buell), Agnes Coolbrith, Sylvia Sessions Lyon (married to Windsor Lyon), Mary Rollins Lightner (married to Adam Lightner), Patty Bartlett Sessions (married to David Sessions), Marinda Johnson Hyde (married to Orson Hyde), Elizabeth Davis Durfee (married to Jabez Durfee), Sarah Kingsley Cleveland (married to John Cleveland), Delcena Johnson, Eliza R. Snow, Sarah Ann Whitney (17 years old), Martha McBride Knight, Ruth Vose Sayers (married to Edward Sayers), Flora Ann Woodworth, Emily Dow Partridge, Eliza Maria Partridge, Almera Johnson, Lucy Walker (17 years old), Sarah Lawrence (17 years old), Maria Lawrence, Helen Mar Kimball (14 years old), Hanna Ells, Elvira Cowles Holmes (married to Jonathan Holmes), Rhoda Richards, Desdemona Fullmer, Olive Frost, Melissa Lott, Nancy Winchester (14 years old) and Fanny Young.
Although there is some historic indication that Smith married more women than those listed here (such as Clarissa Reed Hancock, the mother of John Reed Hancock), the evidence is not conclusive.
Imprisonment and Death
Smith had been imprisoned in Carthage, Illinois for destroying the printing press of the Nauvoo Expositor. The Expositor had denounced (in its only printed edition) "false doctrines" (for instance the "doctrines of many gods") and Smith had then had the printing press burned in the street. In retaliation, an angry mob broke into the prison on June 27, 1844. In an attempt to defend himself (with a pistol which had been smuggled in to him), Smith shot and wounded three men. He was apparently preparing to jump from the unbarred second floor window where he had been incarcerated, but was shot, causing him to fall injured to the ground below. Four men shot him to death on the ground. None was convicted. His brother Hyrum (who was also armed with a pistol) was shot in the face and killed during the same gun-battle. 
- The First Vision Mormon.org
- Translation of the Book of Mormon Mormon.org
- Authority to baptize Mormon.org
- Authority of Apostles Mormon.org
- MORMON ENIGMA: EMMA HALE SMITH (Newell & Avery, University of Illinois Press, Urbana and Chicago, 1994)
- Family Search Familysearch.org
- Wives of Joseph Smith WivesofJosephSmith.org
- Martyr for God JosephSmith.net