Polygamous "marriages" were conducted in secret by Joseph Smith as early as 1833/35 (even though the sealing power wasn't restored until 1836 and D&C 132 outlining the rules of polygamy was not given until 1843) and by a few select members beginning in 1843.
Throughout this time, the Church publicly lied that any devout leaders were involved in polygamy.
John Taylor, the third president of the church, claimed that he believed in keeping all the laws of the United States "except one"…the law in relation to polygamy." (Journal of Discourses, Vol. 317) Most of Joseph Smith's polygamous marriages occurred in Illinois in the early 1840s.
The Illinois Anti-bigamy Law, enacted February 12th, 1833, clearly stated that polygamy was illegal. Bigamy consists in the having of two wives or two husbands at one and the same time, knowing that the former husband or wife is still alive.
It shall not be necessary to prove either of the said marriages by the register or certificate thereof, or other record evidence; but the same may be proved by such evidence as is admissible to prove a marriage in other cases, and when such second marriage shall have taken place without this state, cohabitation in this state after such second marriage shall be deemed the commission of the crime of bigamy, and the trial in such case may take place in the county where such cohabitation shall have occurred.Polygamy as a doctrine was introduced into the LDS Church by Joseph Smith.The practice continued after Joseph’s death in 1844, and was publicly announced in 1852, five years after the Saints arrived in Utah.Note: Beginning in 2013 the Church started releasing essays addressing seldom talked about issues in the church.Three of those essays concern polygamy: Mormon Think provides a link to each essay and a response to them.Mormon Think provides a response to that accusation.) Because the Church now admits some of the things originally written on this page in their essays, some of the topics here are no longer as important as they were before, but we are keeping much of that information here anyhow. The reasons most commonly given by members (even if not published in Church lesson manuals) to justify polygamy are: In 1890, President Wilford Woodruff received a revelation that the leaders of the Church should cease teaching the practice of plural marriage so it would not be in violation of the laws of the land. (From anecdotal information, there is still a large number of members believing this.) Links recording official Church teachings concerning polygamy: Some apologists say that the above points are not officially taught in Church through lesson manuals. However, these things have been taught in Church, whether officially or not.For the latest from the Church and Mormon Think's responses, see: Member beliefs Polygamy was illegal Contradicts 12th Article of Faith More women than men? The writers of this section heard all of the above in Gospel Doctrine and Sunday School classes since childhood.Joseph eventually "married" at least 32 women in addition to Emma Smith, including 7 girls under the age of 18 (the youngest being 14) and at least 11 women who were simultaneously married to other men.If plural marriage is necessary to have more children, then why did Joseph Smith take plural wives who already had husbands and why didn't his plural wives bear him children?It proposed that one reason for Polygamy was that the Church needed to increase it's membership rapidly as it's members were being persecuted.Clearly misinformation is still taught as truth and without clear, consistent correction from the highest leadership, members perpetuate it.