The members of the Church of Jesus Christ of Latter-day Saints had been persecuted for their beliefs ever since Joseph Smith founded the church in New York in 1830. Smith's claim to be a modern-day prophet of God and his acceptance of polygamy proved controversial wherever the Mormons attempted to settle. In 1839, Smith hoped his new spiritual colony of Nauvoo in Missouri would provide a permanent safe haven for the Saints, but anti-Mormon prejudice there proved virulent. Angry mobs murdered Smith and his brother in June 1844 and began burning homes and threatening the citizens of Nauvoo.
Convinced that the Mormons would never find peace in the United States, Smith's successor, Brigham Young, made a bold decision: the Mormons would move to the still wild territories of the Mexican-controlled Southwest. Young had little knowledge of the geography and environment of the West and no particular destination in mind, but trusting in God, he began to prepare the people of Nauvoo for a mass exodus.
On this day in 1846, Young abandoned Nauvoo and began leading 1,600 Mormons west across the frozen Mississippi in subzero temperatures to a temporary refuge at Sugar Grove, Iowa. Young planned to make the westward trek in stages, and he determined the first major stopping point would be along the Missouri River opposite Council Bluffs. He sent out a reconnaissance team to plan the route across Iowa, dig wells at camping spots, and in some cases, plant corn to provide food for the hungry emigrants. The mass of Mormons made the journey to the Missouri River, and by the fall of 1846, the Winter Quarters were home to 12,000 Mormons.
After a hard journey across the western landscape, Young and his followers emerged out onto a broad valley where a giant lake shimmered in the distance. With his first glimpse of this Valley of the Great Salt Lake, Young reportedly said, "This is the place." That year, some 1,600 Mormons arrived to begin building a new civilization in the valley. The next year, 2,500 more made the passage. By the time Young died in 1877, more than 100,000 people were living in the surrounding Great Basin, the majority of them Mormons.
Young, however, had not escaped the troubles that plagued the Church in the East. By early 1848, the Mormons' haven became a U.S. territory after the American victory in the Mexican War. The Mormons had finally found a permanent home along the Great Salt Lake, but its isolation and freedom from persecution was short-lived.