Mormon History, Aug 25, 1845

Apostle Orson Pratt writes in the NEW YORK MESSENGER against Mormons who are teaching that the mortal body "of our martyred prophet and seer, or of any other person, was, or is the especial tabernacle of the Holy Ghost . . ." This is the earliest specific reference to a belief that Joseph Smith was the Holy Ghost in the flesh. Nearly fifty years later Wilford Woodruff would publicly indicate that this was a continued belief among some Mormons. It is still a belief among some Mormon fundamentalists (polygamists) today.

[source: On This Day in Mormon History, http://onthisdayinmormonhistory.blogspot.com]