1857-8 was in progress. As is well known, the Mormons had migrated to the Salt Lake valley when that country was still a possession of Mexico. But the war with Mexico transferred it to the United States, and as it increased in population the responsibilities of territorial government followed. Brigham Young and his people opposed all Federal interference; indeed the Government was not at first disposed to trouble them; and to make such interference as was necessary as light as possible, Brigham Young was himself made first governor of the territory. The movement of people along the California trail had brought to the States the first real knowledge of the condition of things in Utah, and a feeling of prejudice against the Mormons gradually assumed formidable proportions. In 1857 the incoming administration at Washington appointed a new governor, Alfred Cummings, to succeed Young. The ex-governor and his people rebelled and decided that the change should not take place; and to make good their threat they prepared for active resistance.
It therefore became necessary to send a military force to protect the governor and other new officers in the discharge of their duties, and Albert Sidney Johnston was sent in command of the expedition. The Mormons at first got the better of the federal troops; destroyed large quantities of their supplies, and so crippled the usefulness of Fort Bridger as a base that the expedition was threatened with starvation when the winter of 1857-8 approached. Thereupon the Government assumed both a commanding and conciliatory tone. It organized a new military expedition, and it sent commissioners offering amnesty to such of the Mormons as ceased their resistance. These measures resulted in peace before the second military expedition reached the territory. General Johnston and Governor Cummings entered the Mormon capital in June and the authority of the governor was recognized by the people. The second military expedition was stopped at the ford of the South Platte river and turned back.