NAUVOO ERA
The "Nauvoo Era" is an expression used by mormonism at large to refer to the last period (1839-1844) of Joseph Smith's life and the next two "exodus years". Joseph Smith was the founder and first prophet of the Church of Jesus Christ of Latter Day Saints, most commonly called the "Mormon" Church, after the Book Of Mormon, the first volume of Scripture created by the noted religious leader. He created the city of Nauvoo, Illinois and built a temple there (there was a first mormon "temple" in Kirtland,Ohio). After the death of Joseph Smith, several churches, organisations and movements resulted from the teachings of Joseph Smith. Some of them refer specifically to the Nauvoo Era theology, which Joseph Smith developed during this time period and which shows some notable differences with the "standard" christian theologies. However a lot of this theology seems very oriental, both Budhist and Oriental Orthodox and Theosofist elements can be found. The sermon which could be seen as the one that ended Joseph Smith's life, was the "King Follet Sermon", which detailed his new views about eternal life, such as the uncreatability of the soul, (an orthodox view), the eternal nature of matter (a sofist principle) and the progression of man through the eternities, from imperfection to perfection and hence into godhood (a buddhist/hindu principle).
Links where one can read more about this crucial period in mormon history:
[1]website of one of the latest denominations in mormonism called Reformmormonism
[2]wiki article about the city of Nauvoo
[3]Reference of the LDS church's university called Brigham Young University
[4]Compliation by Matthew T Evans of original eyewitness reports of Smith's sermons throughout his Nauvoo period.
[5]Handwritten poem written at the time of Smith's demise
[6]reference to this period in this online archive
[7]article about Nauvoo pageant