April 5, 1841 - Joseph Smith (Age: 35) married Louisa Beaman (Age: 26).
"Louisa Beaman first met Joseph Smith in 1834 when Joseph and several missionaries stayed in the Beaman home in Avon, New York. Louisa’s sister, Mary, remembered the visit: “His society I prized, his conversation was meat and drink to me”. One of the missionaries, Parley P. Pratt, also noted the stay: “Among those whose hospitality we shared in that vicinity was old father Beeman and his amiable and interesting family. He was a good singer, and so were his three daughters; we were much edified and comforted in their society...”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pgs 57,58)
"The Beaman family joined the church and moved to Kirtland, Ohio in 1835. While there, Louisa’s father died at the age of 62. Amid church dissention in Kirtland, Louisa, and her Mother, Sarah, made the trip to Missouri and then finally to Nauvoo. Shortly after arriving in Nauvoo, Louisa’s Mother also died, most likely of malaria, which was rampant. Louisa moved in with her sister Mary and brother-in-law, Joseph Bates Noble." (In Sacred Loneliness: The Plural Wives of Joseph Smith pgs 58,59)
"In the fall of 1840 Joseph Smith taught Joseph Bates Noble, “the principle of celestial marriage or plural marriage”, which Joseph said was given by revelation. Joseph then asked Noble to perform a marriage ceremony between himself and twenty-five-year-old Louisa. Smith also warned, “In revealing this to you, I have placed my life in your hands, therefore do not in an evil hour betray me to my enemies.”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pg 59; Mormon Enigma: Emma Hale Smith pg 95)
"Joseph and Louisa were married on April 5, 1841, “in a grove Near Main Street in the City of Nauvoo, The Prophet Joseph dictating the ceremony and Br Nobles repeating it after him.”, remembers Erastus Snow, Louisa’s brother-in-law. To help keep the union secret, Louisa wore a man’s hat and coat as disguise. Joseph Bates Noble recalled that after the ceremony, the couple spent their wedding night, “Right straight across the river at my house”. Noble said he encouraged them to, “Blow out the lights and get into bed, and you will be safer there”" (Mormon Polygamy: A History pgs 6, 23; Mormon Enigma: Emma Hale Smith pg 95, In Sacred Loneliness: The Plural Wives of Joseph Smith pgs 59,60)
"After Joseph Smith’s death, Louisa married Brigham Young. Louisa bore five children by Young, all of whom preceded her in death. Tragically, Louisa died of breast cancer at the age of 35." (In Sacred Loneliness: The Plural Wives of Joseph Smith pg 69)
"For many years, Louisa Beaman was widely recognized as the first plural wife of Joseph Smith. In 1851, the city now known as Parowan, Utah was christened Fort “Louisa”. According to John D. Lee, this was, “ in honor of the first Woman who listened to the light & voice of Revelation - & yielded obedience to the Seal of the covenant...for this noble act, her Name is held in honorable rememberance in the History of the Saints”" (In Sacred Loneliness: The Plural Wives of Joseph Smith pg 55; Mormon Polygamy: A History pg 27)
Source Material: http://wivesofjosephsmith.org/04-LouisaBeaman.htm
