  the nauvoo legion was a state authorized militia of the city of nauvoo, illinois. with growing antagonism from surrounding settlements it came to have as its main function the defense of the city of nauvoo, illinois, and surrounding mormon areas of settlement. to curry political favor with the saints, the illinois state legislature granted nauvoo a liberal city charter that gave the nauvoo legion extraordinary independence. led by joseph smith, jr., founder of the latter day saint movement and mayor of nauvoo, the legion quickly became a formidable concentration of military power in the american west. in 1844, after a controversy stemming from the nauvoo city council's suppression of a nauvoo newspaper critical of smith and his church's policies, smith mobilized the legion and declared martial law. arrested for treason, smith was assassinated by a mob. soon thereafter, the nauvoo charter was revoked, and the nauvoo legion lost its official sanction as an arm of the illinois militia. after the revocation of the nauvoo charter, the unsanctioned nauvoo legion continued to operate under the command of brigham young, leader of the movement's largest faction, the church of jesus christ of latter-day saints (lds church). young led the latter-day saints to what later became the territory of utah. in utah the territorial militia used the name of nauvoo legion. it was mobilized in opposition to the united states army during the utah war. it was permanently disbanded in 1887 as part of the edmunds-tucker act, which disincorporated the lds church as part of congress's efforts to punish it for its practice of polygamy. ==formation== in 1839, joseph smith relocated his followers&mdash;the mormons&mdash;from a hostile environment in missouri to commerce, illinois which he renamed nauvoo. voter-conscious illinois democrats and whigs (including abraham lincoln) passed a bipartisan city-state charter for nauvoo in 1840. on december 16 the governor signed it into law, granting smith and the city of nauvoo broad powers. among these was the authority to create a "body of independent militarymen". this force was a militia similar to others in illinois, and it became known as the "nauvoo legion". at its peak, the militia had, by conservative estimates, at least 2,500 troops, in comparison to the approximately 8,500 troops within the entire united states army as of 1845.. the legion was organized into two regiments (called cohorts) of infantry and one regiment of cavalry. a few light cannons were also attached. 
1870_disestablishments Church_of_Christ_(Latter_Day_Saints) History_of_The_Church_of_Jesus_Christ_of_Latter-day_Saints History_of_the_Latter_Day_Saint_movement Latter_Day_Saint_movement_in_Illinois Nauvoo_Legion Organizations_established_in_1840 Pre-statehood_history_of_Utah The_Church_of_Jesus_Christ_of_Latter-day_Saints_in_Utah United_States_private_paramilitary_groups Utah_War Utah_in_the_American_Civil_War