On 27 June 1844, in Carthage, Illinois, the Prophet Joseph Smith was murdered by an anti-Mormon mob along with his brother, Hyrum Smith, patriarch to the Church of Jesus Christ of Latter-day Saints.  John Taylor, later to become third president of the Church, was grievously wounded in the same attack.

The official announcement of their martyrdom, based at least in part on the personal account of John Taylor, now appears in the Doctrine and Covenants:

https://www.lds.org/scriptures/dc-testament/dc/135?lang=eng

Also canonized now is Joseph Smith’s recollection of the visit to him of the Angel Moroni, which includes this passage:

He called me by name, and said unto me that he was amessenger sent from the presence of God to me, and that his name was Moroni; that God had a work for me to do; and that my name should be had for good and evil among all nations, kindreds, and tongues, or that it should be both good and evil spoken of among all people.  (Joseph Smith – History 1:33)

That prophecy has been confirmed, in profuse abundance.

Every day, around the world, scores of thousands of missionaries and millions of ordinary Latter-day Saints share their confidence in the testimony of Joseph Smith to his encounters with God.  And, every day, around the world, he’s condemned, derided, and maligned, and his testimony rejected.

I declare, today, my own conviction that God lives, that Jesus is the resurrected, atoning Savior of humankind, and that, in the nineteenth century, in a grove of trees not far from Palmyra, New York, they appeared to the young farm boy Joseph Smith, calling him as a prophet and commencing the restoration of the Gospel and the Church.