LDS History, May 13, 1857

-- May 13, 1857
Parley P. Pratt murdered in Arkansas. (1)

Apostle Parley P. Pratt is murdered by Hector McLean and two others near Van Buren, Arkansas. Pratt had married McLean's former wife in plural marriage. Pratt was acquitted on charges of interfering in McLean's marriage a few days earlier. (2)

[Quorum of the Twelve] Parley P. Pratt is assassinated. (3)

-- May 20, 1857
[Utah War] President James Buchanan, relying upon the negative accusations of several, while ignoring Mormon denials, and without any investigation, was convinced that the Mormons were in rebellion against the United States. He decided to replace Gov. Brigham Young, and without giving him any notice, and without the required Congressional approval (Congress was in recess), proceeded to make his new appointments and issued orders for a large military escort. (4)

-- May 26, 1857
[Utah War] Gen. Winfield Scott advised John B. Floyd against the expedition at that time for several reasons, including the lateness of the start. (4)

-- May 28, 1857
[Deseret] Winfield Scott, General-in-Chief of the U.S. Army, announces the creation of the Military Department of Utah, to be assembled at Fort Leavenworth (Poll & MacKinnon 1994, p. 30). (5)

U.S. President James Buchanan sent 2,500 troops to Utah under Albert Sidney Johnston, beginning the Utah War. (1)

[Utah War] Against Scott's counsel, Floyd ordered 2500 troops to assemble at Fort Leavenworth (1200 miles from SLC) to escort the new governor to Utah. Gen. William S. Harney, Commander of Fort Leavenworth, was appointed Commander of the Utah Expetition, receiving his orders from Secretary of War, John B. Floyd. No indication of the Army's mission was included. (4)

-- Jun 10, 1857
[Utah War] The government contract to carry mail to Utah by the Brigham Young Express and Carrying Company (called the Y. X. Company) was cancelled. Mail service to Utah was thus discontinued, cutting off the normal flow of information which would have alerted Gov. Young that he was to be replaced and, further, that an army was preparing to march to Utah. (4)

-- Jun 29, 1857
[Deseret] U.S. President James Buchanan declares Utah in rebellion against the U.S. government, and mobilizes a regiment of the U.S. army, initially led by Col. Edmund Alexander. (5)

[Utah War] Instructions were given by Gen. George W. Lay, aid to General Scott, to Gen. William S. Harney regarding his command of the expedition to Utah. He was informed that the community and civil government were in rebellion and the Army's purpose was to assist the new governor to establish and maintain law and order as a posse comitatus. The troops were not to attack any body of citizens without orders, except for sheer self-defence. (4)

-- Jul 1, 1857
[Utah War] Without explalnation, the postmaster at Independence, Missouri refused to release the mail to the Y. X. Company for delivery to Utah. They discovered that their mail contract had been cancelled and that a secret operation was planned to send 2500 federal troops to Utah. (4)

-- Jul 4, 1857
[Utah War] Independence Day was celebrated as usual with intense patriotism. (4)

-- Jul 5, 1857
[Deseret] Brigham Young refers in a sermon to "rumors" that the U.S. is sending 1,500 to 2,000 troops into the Utah Territory, and warns them, possibly sarcastically, that if people enter the territory and don't "behave themselves", they will be subject to a "Vigilance Committee", and the Danites will "bite[] their heels" (Young 1857a, p. 5). (5)

-- Jul 11, 1857
A. Cumming, of Georgia, was appointed governor of Utah. (6)

-- Jul 13, 1857
[Deseret] President Buchanan appoints Alfred Cumming governor of Utah, and directs him to accompany the military forces into Utah (Poll & MacKinnon 1994, p. 30). (5)

1 - Hemidakaota, "Church Chronology from 1800-2000,"
2 - Wikipedia, 19th Century (Mormonism),
3 - Wikipedia, Chronology of the Quorum of the Twelve Apostles (LDS Church),
4 - Hale, Van, Mormon Miscellaneous, Utah War Chronology,
5 - Wikipedia, Utah War,
6 - Richards, Franklin Dewey and Little, James A., Compendium of the Doctrines of the Gospel, Church Chronology, Ch.66, p.306
Mormon History Timeline /Chronology