Mormonism traces its origins to the Church of Christ founded by Joseph Smith, Jr. on April 6, 1830 in Western New York.[12] Roughly a decade earlier, the young Joseph was seeking a remission of his sins. Confused by the doctrines of competing denominations, he went into a grove of trees to pray about which church to join. Joseph said that during his prayer, the Lord appeared to him in a “pillar of light” and instructed him not to join any of the churches.[13] A few years later Smith said that an angel directed him to a nearby hillside where lay buried a book written on golden plates containing the religious history of an ancient people.[14] Smith claimed to have translated the book, and in March 1830 he published the Book of Mormon, named after Mormon, the ancient prophet-historian who compiled the book. The Book of Mormon drew many initial converts to the church. Church members were later called Mormons, Latter Day Saints, or just Saints.[15]

Smith intended to establish the city of Zion (or the New Jerusalem) in North America.[16] In 1831, the church moved to Kirtland, Ohio (the eastern boundary of Zion),[17] and began establishing an outpost in Jackson County, Missouri (Zion’s “center place”),[18] where he planned to eventually move the church headquarters.[19] In 1833, Missouri settlers, alarmed by the rapid influx of Mormons, expelled them from Jackson County.[20] After leading Zion’s Camp, an unsuccessful expedition to recover the land,[21]Smith began building a temple in Kirtland, where the church flourished.[22][23] The Kirtland era ended in 1838, after the failure of a church-sponsored bank caused widespread defections,[24] and Smith regrouped with the remaining church in Far West, Missouri.[25] During the fall of 1838, tensions escalated into violent conflicts with the old Missouri settlers.[26] Believing the Saints to be in insurrection, the Missouri governor ordered the Saints’ expulsion from Missouri.[27] In 1839, the Saints converted a swampland on the banks of the Mississippi River into Nauvoo, Illinois, which became the church’s new headquarters.[28]

Shortly after arriving in Nauvoo, the Saints began construction of a new temple. The city grew rapidly as missionary converts immigrated westward from Europe and elsewhere.[29] Meanwhile, Smith introduced several doctrinal developments and organizational changes, including temple ceremonies, the doctrines of sealing, eternal progression[30] (or exaltation), plural marriage,[31] the organization of the church into stakes[32] and wards, the organization of the Relief Society for women, and the Council of Fifty, an organization representing a future theodemocratic ”Kingdom of God” on the earth.[33] Smith also published the story of his First Vision, in which the Father and the Son appeared to him while he was about 14 years old.[34] Long after Smith’s death, this vision would come to be regarded by some Mormons as the most important event in human history after the birth, ministry, and resurrection of Jesus Christ.[35]

On June 27, 1844, Joseph Smith and his brother Hyrum were killed by a mob in Carthage, Illinois.[36] Because Hyrum was Joseph’s logical successor,[37] their deaths caused a succession crisis,[38] and Brigham Young assumed leadership over the majority of Saints.[39] Young had been a close associate of Smith’s and was seniorapostle of the Quorum of the Twelve.[40] Smaller groups of Latter Day Saints followed other leaders to form other denominations of the Latter Day Saint movement.[41]