Nevertheless, and notwithstanding, Church leaders like Brigham Young and John Taylor were still unaware of Joseph Smith's claim of seeing God the Father and Jesus Christ 40 years after the fact (and I use the term "fact" loosely).  That's because Joseph's "first vision" was a consistently changing story that was virtually unknown to early Latter-day Saints. Over the years Joseph's story changed from an event in the year 1823 to 1821 to 1820.

Below is another early account of the same event as told by Joseph Smith:

And when I considered upon these things my heart exclaimed well hath the wise man said the <it is a> fool <that> saith in his heart there is no God my heart exclaimed all all these bear testimony and bespeak an omnipotent and omnipreasant power a being who makith Laws and decreeeth and bindeth all things in their bounds who filleth Eternity who was and is and will be from all Eternity to Eternity and when I considered all these things and that <that> being seeketh such to worship him as worship him in spirit and in truth therefore I cried unto the Lord for mercy for there was none else to whom I could go and to obtain mercy the Lord heard my cry in the wilderness and while in <the> attitude of calling upon the Lord <in the 16th year of my age*> a piller of fire light above the brightness of the sun at noon day come down from above and rested upon me and I was filled with the spirit of god and the <Lord> opened the heavens upon me and I saw the Lord.

And he spake unto me saying Joseph <my son> thy sins are forgiven thee. go thy <way> walk in my statutes and keep my commandments behold I am the Lord of glory I was crucifyed for the world that all those who believe on my name may have Eternal life <behold> the world lieth in sin and at this time and none doeth good no not one they have turned asside from the gospel and keep, not <my> commandments they draw near to me with their lips while their hearts are far from me and mine anger is kindling against the inhabitants of the earth to visit them acording to th[e]ir ungodliness and to bring to pass that which <hath> been spoken by the mouth of the prophets and Ap[o]stles behold and lo I come quickly as it [is] written of me in the cloud <clothed> in the glory of my Father.

And my soul was filled with love and or many days I could rejoice with great joy and the Lord was with me but [1] could find none that would believe the hevnly vision nevertheless I pondered these things in my heart..."
* in the 16th year of my age -- if this means "16 years old", this dates the vision to 1822;

if it means "15 years old" it would have been 1821, but not 1820 as told today.

1 The preceding is a transcript of Joseph Smith's earliest known account, which has been dated to 1832, and is the only version of a vision written in Joseph Smith's own hand. <angled brackets signify above-the-line insertions made in the original manuscript>;     [square brackets are editorial comments or additions].

2 A second account of the vision was made in 1835 to Robert Matthews (Robert Matthias). Joseph says he was "about 14 years old at    the time of the vision. [ This would have been 1820 ]. In this account of his vision Smith said he saw two personages, not just one as in the first account. In addition he said "I saw many angels in this vision."

3 In a third variant of the vision to Erastus Holmes of Newbury Ohio, Smith told him that that he had received only a "visitation of angels". (This does not square with his first account of the vision in which angels were not mentioned).

4 Since Smith's earliest account, several other renditions have been made by him, but they differ in considerable detail. In the 1832 account Smith saw only one personage in 1821 (or 1822). One of several accounts (the last one) dictated six years later in 1838, has Joseph Smith see "two personages (whose brightness and glory defy all description) floating above me in the air..."

This fourth account is the one upon which mormon scholars rely on as the bedrock true faith of Mormonism. It is the account which, as the official version of the truth, made its entry into the Mormon canon in the pearl of Great price. Mormon scholars sometimes dread the fact that Smith can't remember how old he was when he had his vision. Inaccuracy hurts, especially when one is translating unique golden plates, and translating them correctly, indeed.  HOW they were translated should leave NO room for error.  From God's "mouth" to the ear of man.  A direct "translation".

Mormon scholars often fear that the fact that Smith's accounts of his visions are not recounted correctly, owing to the several variations of visions. They are afraid that Mormonism may not be taken seriously -- after all, who is to say Smith's vision might not mistakenly be lumped in with visions of false prophets, such as that of Norris Stearns, whose "vision" introduces this article. Visions seem to have been common in the early seventeenth century in North America, (as they are today, except no one considers them seriously.).
In fact, according to Mormon scholar Lamar Peterson in his book "The Creation of the Book of Mormon", the American theological landscape was filled with accounts of visions in the early 1800's.