The oft asked question about the practice of polygamy in early Mormon history is: How many wives did Brigham Young have?
The question isn't as easily answered as asked. When polygamy was a part of Mormon culture, there were different types of marriages or "sealings."
It is hard to determine how many wives Young actually lived with in the normal sense of husband and wife because of the practice of "sealing." Sealings, meaning a ceremony performed by Mormon church authorities that link a man and a woman, could be of two types. The most common, and the only one currently practiced by the Mormon church, is a ceremony that seals a man and a woman for time (mortal life) and eternity. A second form could seal a woman to one man for time and another for eternity. Such ceremonies usually occurred when a widow was sealed to her dead husband for eternity and to a living husband for time in the same ceremony. It was understood that any children by the second husband would be considered the progeny of the first. In the early days of the Mormon church, these relationships were commonly called proxy marriages.
According to Church of Jesus Christ of Latter-day Saints (LDS) historical records, Brigham Young was sealed to as many as 56 women. Many of the wives to whom Young were sealed were widows or elderly women for whom he merely cared or gave the protection of his name.
When asked by Horace Greeley in 1859, Brigham Young said that he had 15 wives, "but some of those sealed to me are old ladies whom I regard rather as mothers than wives. . ." This answer reflects the complicated nature in the definition of "plural wife." As to the number of wives with whom it is known that he had conjugal relations, sixteen wives bore him 57 children (46 of whom grew to maturity).
Several of his wives lived in the Lion House or the Beehive House; others had separate residences.
At the time of his death on August 23, 1877, Young had married 56 women--19 predeceased him, 10 divorced him, 23 survived him, and 4 are unaccounted for. Of the 23 who survived him, 17 received a share of his estate while the remaining 6 apparantly had non conjugal roles.
Source: Jeffery Ogden Johnson, "Determining and Defining `Wife': The Brigham Young Households," Dialogue: A Journal of Mormon Thought, Vol. 20, No. 3, Fall 1987; Leonard J. Arrington, Brigham Young: American Moses, Knopf, New York, 1985.