Nauvoo Temple cornerstones laid. (1)
-- 1841 April 6
Cornerstones of the Nauvoo Temple are laid. (2)
-- April 6, 1841
[Joseph Smith] Nauvoo, Illinois. Joseph Smith supervised the laying of the four Nauvoo Temple cornerstones and attended a military parade celebrating the 11th anniversary of the Church. (3)
-- 1841, April 6
[Joseph Smith] Cornerstones are laid for the Nauvoo Temple. (4)
-- 6 Apr. 1841
[Lucy Mack Smith] The cornerstone of the Nauvoo temple is laid with much ceremony. (5)
-- 1841 Apr 6
[Lucy Mack Smith] Cornerstone laid for the Nauvoo Temple. (6)
-- 8 April 1841 - 25 May 1842
[1st Presidency Changes] Joseph Smith, Jr. Hyrum Smith (Assistant President) John C. Bennett (never ordained an apostle, Assistant President) Sidney Rigdon (never ordained an apostle) William Law (never ordained an apostle) John Smith (never ordained an apostle, Counselor) John C. Bennett called as Assistant President (7)
-- 1841 April 8
Lyman Wight is ordained an apostle and member of the Quorum of the Twelve Apostles. (2)
-- April 8, 1841
[Quorum of the Twelve] Lyman Wight ordained. (8)
-- 1841 April 20
[Wilford Woodruff] Sails from England (9)
-- 29 Apr. 1841
[Lucy Mack Smith] Samuel Harrison Smith marries Levira Clark. Some sources also give the marriage date as 3/30 May 1841. Lucy mistakenly gives the marriage date as 29 April 1842. That was the date of their first daughter's birth. (5)
-- May 4, 1841
[Joseph Smith] Nauvoo, Illinois. Joseph Smith wrote a letter to Oliver Granger, his agent in Kirtland, Ohio. (3)
-- May 14, 1841
[Joseph Smith] Nauvoo, Illinois. Joseph Smith received an agreement from Ebenezer F. Wiggins. (3)
Footnotes:
1 - Encyclopedia of Mormonism, Vol. 4, Appendix 2: A Chronology of Church History
2 - http://en.wikipedia.org/wiki/19th_century_(Mormonism)
3 - BYU Studies Journal, volume 46, no. 4: A Chronology of the Life of Joseph Smith
4 - Teachings of Presidents of the Church: Joseph Smith, The Church of Jesus Christ of Latter-day Saints, Salt Lake City, Utah
5 - Lucy's Book: A Critical Edition of Lucy Mack Smith's Family Memoir, Edited by Lavina Fielding Anderson, 2001, Signature Books
6 - History of Joseph Smith by His Mother: Revised and Enhanced by Scot Facer Proctor Maurine Jensen Proctor
7 - http://en.wikipedia.org/wiki/First_Presidency_(LDS_Church)#Chronology_of_the_First_Presidency
8 - http://en.wikipedia.org/wiki/Chronology_of_the_Quorum_of_the_Twelve_Apostles_(LDS_Church)
9 - Wilford Woodruff's Journals 1833-1898: Typescript Edited by Scott G. Kenney, Signature Books, Midvale, Utah. Chronology
Mormon History Timeline /Chronology
http://lds-church-history.blogspot.com/