October 23, 1835 – The Prophet Joseph Smith invited Oliver Cowdery, David Whitmer, Hyrum Smith, John Whitmer, Sidney Rigdon, Samual H. Smith, Frederick G. Williams, and W. W. Phelps, to his home to unite in prayer, “with one voice, before the Lord,” to pray for deliverance from the afflictions and difficulties of the Saints, especially those in Missouri. (History of Church, 3:166)
October 30, 1838 – A mob under the leadership of Col. Wm. O. Jennings attacked a little settlement of Saints at Haun’s Mill, Caldwell Co., Missouri, and killed and mortally wounded several Saints. Others were severely wounded, but recovered.
October 29, 1839 – Joseph Smith, jun., accompanied by Sidney Rigdon, Elias Higbee and O. Porter Rockwell left Commerce for Washington, D. C., to lay the grievances of the Saints before the President and Congress of the United States.
October 23, 1843 – The Prophet Joseph met with the members of the Twelve who had just returned from their missions and gathered the money donated by the Saints in the East for the building of the Temple in Nauvoo. He immediately “gave directions to send to St. Louis for groceries and different articles necessary for the Temple and the workmen thereon.” (History of Church 6:60-61)
October 23, 1903 – Brigham Young Academy in Provo, Utah, officially changes its name to Brigham Young University.
October 23, 1976 – The first missionaries enter the island nation of Micronesia.
October 23, 1985 – A new genealogical library in Salt Lake City, Utah, later renamed the Family History Library, is dedicated by President Gordon B. Hinckley of the First Presidency.
Taken from History of Church; & Church Chronology by Andrew Jenson