President of the Church

In the Latter Day Saint movement, the President of the Church is generally considered to be the highest office of the church. It was the office held by Joseph Smith, founder of the movement, and the office assumed by many of Smith's claimed successors, such as Brigham Young, Joseph Smith III, Sidney Rigdon, and James Strang. Several other titles have been associated with this office, including First Elder of the church,Presiding High Priest,President of the High Priesthood,Trustee-in-Trust for the church,Prophet,Seer,Revelator, and Translator. Joseph Smith was known by all of these titles in his lifetime (although not necessarily with consistency).

Smith died in 1844 without having indisputably established who was to be his successor. Therefore, his death was followed by a succession crisis in which various groups followed leaders with succession claims. Years later, the office of President was reorganized in many of the resulting Latter Day Saint denominations, the largest of which are The Church of Jesus Christ of Latter-day Saints (LDS Church), the Community of Christ (formerly the Reorganized Church of Jesus Christ of Latter Day Saints), and The Church of Jesus Christ (Bickertonite). Some smaller denominations, such as the Church of Christ (Temple Lot), reject the office as an unscriptural creation.

The concept that the Church of Christ would have a single presiding officer arose in late 1831. Initially, after the church's formation on April 6, 1830, Joseph Smith referred to himself as merely "an apostle of Jesus Christ, and elder of the church." However, there was one other apostle—Oliver Cowdery—and several other elders of the church, making the formal hierarchy of the church unclear.

...
Wikipedia