Who Is Thomas S. Monson? Mormon Church President Dead at 90

President of the Church of Jesus Christ of Latter Day Saints, Thomas Monson, talks during the fourth session of the 178th Semiannual General Conference of the church, on October 5, 2008, in Salt Lake City. Monson has died at the age of 90. George Frey/Getty Images

Thomas S. Monson, the president and leader of the Mormon faith, the Church of Jesus Christ of Latter-day Saints, has died aged 90 after 10 years presiding over the Utah-based church.

Monson's death late Tuesday evening was announced by the church in an email from spokesman Eric Hawkins.

Related: Mormon Cult Leaders Indicted for Forcing Almost Daily Sex Rituals With Underage Girls, Said God Would Destroy Their Families if They Refused

"With tender feelings we announce that Thomas S. Monson, president and prophet of The Church of Jesus Christ of Latter-day Saints, died this evening at 10.01 p.m. in his home in Salt Lake City," the statement read according to The Salt Lake Tribune.

Monson, who was considered a prophet by 16 million Mormons, died surrounded by his family, it added.

During his tenure as the president of the church and after more than five decades as a Mormon apostle—one of 12 that form one of the highest governing bodies of the faith—Monson was at the center of seismic shifts in doctrine.

Under Monson's leadership, though he was in poor health at the time, the Church of Jesus Christ of Latter-day Saints decided to label same-sex couples as apostates who could be excommunicated from the church. Excommunication in the faith often means the severing of deep family ties because of the central nature of the church in day to day life.

The policy was met with a backlash by LGBT rights advocates and progressive quarters of the Mormon church, who said the position was not Christian.

Monson also played a role in forming an alliance of faith groups in the first year of his presidency in 2008 to advocate the passing of California's Proposition 8. The ballot measure, which eventually passed, defined marriage exclusively as union between a man and a woman. Once again LGBT rights advocates and many Mormon centers were left alienated and angered.

Other areas of Monson's leadership were more progressive but this also led to a backlash from conservative members of the Mormon faith. Under the Utah Compact the the church called for more humane immigration policies. Monson also called for introspection over some of the darker areas of Mormonism's past including polygamy, which the church ended in 1890, and institutional racism, which barred African Americans from the priesthood and in the earliest days of the religion was used to justify slavery.

Other changes he spearheaded included the lowering of the age for Mormon missionaries from 19 years of age to 18 for men and from 21 to 19 for women. The Salt Lake Tribune reported that the move in October 2012 changed the gender dynamic in missionary work and increased the number of Mormon women going on postings.

Reforms to private religious colleges tied to the church at the time then facilitated the creation of 60 new missions around the world.