Polygamy in the Church of Jesus Christ of Latter Day Saints, called plural marriage, is generally believed to have originated with the founder of Mormonism, Joseph Smith. According to several of his associates, Smith taught that polygamy was a divine commandment and practiced it personally, by some accounts marrying between 30 and 40 wives, some of whom had existing marriages to other men. Evidence for Smith's polygamy is provided by the church's "sealing" records, affidavits, letters, journals, and diaries. Smith's son Joseph Smith III, his widow Emma Smith, and the Reorganized Church of Jesus Christ of Latter Day Saints (RLDS Church, now called Community of Christ) challenged the evidence and taught that Joseph Smith had opposed polygamy. They instead stated that Brigham Young, the head of the Church of Jesus Christ of Latter-day Saints (LDS Church), introduced plural marriage after Smith's death. In 1852, leaders of the Utah-based LDS Church publicly announced the doctrine of polygamy.
1830s: origins
When polygamy was introduced into the Latter Day Saint movement is uncertain.
===Possible revelation in 1831===<!--link from "Current state of polygamy in the Latter Day Saint movement" directs here -->
thumb|right|200px|A photograph of part of [[W. W. Phelps (Mormon)|W. W. Phelps' transcript of what Phelps said was an 1831 polygamy revelation by Joseph Smith. The original is held by the LDS Church's historical department.]]
Some scholars believe that Smith transcribed a revelation recommending polygamy on July 17, 1831. This revelation is described in a letter to Brigham Young written in 1861 by an early Mormon convert, William W. Phelps,