Latter Day Saint polygamy in the late-19th century

Possibly as early as the 1830s, followers of the Latter Day Saint movement (also known as Mormonism), were practicing the doctrine of polygamy or "plural marriage". After the death of church founder Joseph Smith, the doctrine was officially announced in Utah Territory in 1852 by Mormon leader Brigham Young.

Source: Wikipedia — Latter Day Saint polygamy in the late-19th century (CC BY-SA 4.0)