Pocatello was born 1815. He was the leader at the time of the United States' arrival into Utah in the late 1840s. In the 1850s, he led a series of attacks against emigrant parties in the Utah Territory and along the Oregon Trail. He gained a reputation among Mormon leaders and Indian agents as a leader of a band of Native Americans. Brigham Young, the leader of the Mormons, attempted a policy of reconciliation and appeasement of the Shoshone, but the arrival of the United States Army in the Utah Territory in 1858 exacerbated tensions between the emigrants and the Shoshone.