What Is the Church of Jesus Christ of Latter-day Saints?

FX's true crime show Under the Banner of Heaven explores how religious fundamentalism led to the tragic deaths of 24-year-old Brenda Wright Lafferty and her 15-month-old daughter Erica.

The drama, which is based on Jon Krakauer's nonfiction book of the same name, examines this case in light of The Church of Jesus Christ of Latter-day Saints, also known as the LDS church or Mormon church.

It does so by recounting the faith's founding and also how Mormon detective Jeb Pyre (Andrew Garfield) struggles with his beliefs while investigating the horrific 1984 murders.

Here is everything you need to know about the Christian faith and its origins.

What Is The Church of Jesus Christ of Latter-day Saints?

Under the Banner of Heaven
Andrew Garfield as Mormon Detective Jeb Pyre in "Under the Banner of Heaven." Michelle Faye/FX

The LDS church is an American homegrown faith that was founded by Joseph Smith Jr. in the 1820s and is believed to have restored the true Church of Christ.

Smith proclaimed he was visited by an angel named Moroni in 1823 who told him of a sacred text inscribed on gold plates that was hidden under a rock fourteen hundred years earlier.

The morning after the divine visitation, Smith went to the location of the rock on Hill Cumorah, in New York, and found the gold plates. But they were taken away from him by the angel Moroni after he attempted to remove them from their hiding place.

Moroni commanded Smith visit the site every year on September 22 until the time was right for the texts to be removed, so claimed Smith, and he was only allowed to remove the gold plates in 1827 after bringing new wife Emma Hale to the site upon the angel's command.

It took several attempts for Smith to translate the divine script, which contained a language described as "reformed Egyptian," per Krakauer, but in June 1829 he completed the translation.

Five thousand copies of the 588-page book were printed nine months later, and it was titled The Book of Mormon. The text became the basis for the religion Smith formally founded on April 6, 1830: The LDS church.

What is The Book of Mormon?

The Book of Mormon tells the history of an ancient Hebrew tribe led by a man named Lehi who, the text claims, traveled to North America with his large family some 600 years before the birth of Jesus Christ.

Lehi bequeathed the tribe to his youngest son Nephi, much to his brother Laman's disapproval, and upon their father's death the two formed rival clans: the Nephites and the Lamanites.

The Book of Mormon claims that following his resurrection, Jesus Christ traveled to North America to visit the two clans to share his new gospel, and urged them to work together.

According to Krakauer, the two clans worked together for several hundred years but then a rift led to a full-blown war between them in which the Lamanites slaughtered the 230,000 Nephites, including their leader Mormon.

The Book of Mormon claimed the Lamanites were ancestors of Native Americans, who lost memory of their heritage. Krakauer explained that modern DNA analysis has since disproven this claim.

Mormon's son Moroni recounted the last chapter of The Book of Mormon, and later became the same angel to visit Smith and tell him of the location of the ancient gold plate text.

Under the Banner of Heaven airs Thursdays on Hulu.

The Angel Moroni and Joseph Smith
Engraving showing the Angel Moroni delivering the plates of the Book of Mormon to Joseph Smith, of the Church of Jesus Christ of Latter Day Saints, 1907. Smith Collection/Gado/Getty Images