Joseph Smith

Joseph Smith was a man of integrity. He was persecuted for saying what he knew to be true. Even though he was arrested and jailed many times, tarred and feathered, and tormented in other ways, Joseph never denied his testimony:

"I had actually seen a light, and in the midst of that light I saw two Personages, and they did in reality speak to me; and though I was hated and persecuted for saying that I had seen a vision, yet it was true; and while they were persecuting me, reviling me, and speaking all manner of evil against me falsely for so saying, I was led to say in my heart: Why persecute me for telling the truth? I have actually seen a vision; and who am I that I can withstand God, or why does the world think to make me deny what I have actually seen? For I had seen a vision; I knew it, and I knew that God knew it, and I could not deny it, neither dared I do it; at least I knew that by so doing I would offend God, and come under condemnation" (Joseph Smith—History 1:25).
In February 1832 the Prophet Joseph Smith and Elder Sidney Rigdon recorded:

"And now, after the many testimonies which have been given of him, this is the testimony, last of all, which we give of him: That he lives!
"For we saw him, even on the right hand of God; and we heard the voice bearing record that he is the Only Begotten of the Father—
"That by him, and through him, and of him, the worlds are and were created, and the inhabitants thereof are begotten sons and daughters unto God" (D&C 76:2224).
Joseph Smith's martyrdom on 27 June 1844 in Carthage, Illinois, sealed his testimony (see D&C 135:3).

The Church of Jesus Christ of Latter-day Saints has its foundation in that testimony and in the revelations Joseph Smith received, the sacred truths he taught, and the authority of God's priesthood restored through him. Copied from http://www.lds.org/hf/art/display/1,16842,4218-1-4-16,00.html