Called "the darkest deed of the nineteenth century," the brutal 1857 murder of 120 men, women, and children at a place in southern Utah called Mountain Meadows remains one of the most controversial events in the history of the American West. Although only one man, John D. Lee, ever faced prosecution (for what ranks as one of the largest mass killings of civilians in United States history), many other Mormons ordered, planned, or participated in the massacre of Arkansas emigrants as they headed through southwestern Utah on their way to California. Special controversy surrounds the role in the 1857 events of one man, Brigham Young, the fiery prophet of the Church of Jesus Christ of Latter-day Saints who led his embattled people to the "promised land" in the valley of the Great Salt Lake. What exactly Brigham Young knew, and when he knew it, are questions that historians still debate.