the early 19th century from Canada and the United States. The city of Provo, Utah, was named for one Étienne Provost, who visited the area in 1825. The city of Ogden, Utah, was named after Peter Skene Ogden, a Canadian explorer who traded furs in the Weber Valley. In late 1824, Jim Bridger became the first known English-speaking person to sight the Great Salt Lake. Due to the high salinity of its waters, he thought he had found the Pacific Ocean; he subsequently learned this body of water was a giant salt lake. After the discovery of the lake, hundreds of American and Canadian traders and trappers established trading posts in the region. In the 1830s, thousands of migrants traveling from the Eastern United States to the American West began to make stops in the region of the Great Salt Lake, then known as Lake Youta. Latter Day Saint settlement (1847) Following the death of Joseph Smith in 1844, Brigham Young, as president of the Quorum of the Twelve, became the leader of the LDS Church in Nauvoo, Illinois. To address the growing conflicts between his people and their neighbors, Young agreed with Illinois Governor Thomas Ford in October 1845 that the Mormons would leave by the following year. Young and the first group of Mormon pioneers reached the Salt Lake Valley on July 24, 1847. Over the next 22 years, more than 70,000 pioneers crossed the plains and settled in Utah. For the first few years, Brigham Young and the thousands of early settlers of Salt Lake City struggled to survive. The arid desert land was deemed by the Mormons as desirable as a place where they could practice their religion without harassment. Settlers buried thirty-six Native Americans in one grave after an outbreak of measles occurred during the winter of 1847. The first group of settlers brought African slaves with them, making Utah the only place in the western United States to have African slavery. Three slaves, Green Flake, Hark Lay, and Oscar Crosby, came west with the first group of settlers in 1847. The settlers also began to purchase Indian slaves in the well-established Indian slave trade, as well as enslaving Indian prisoners of war. Utah was Mexican territory when the first pioneers arrived in 1847. Early in the Mexican–American War in late 1846, the United States had taken control of New Mexico and California. The entire