One of the first converts to the LDS church, Parley Parker Pratt (1807-57) would eventually become early Mormonism's most famous and widely published defender. Born in western New York, he converted to Mormonism in late 1830 and was called to the Quorum of Twelve Apostles five years later as one of its founding members. He was strong-willed and largely self-educated, as his vitae reflects: he served several missions for the church; participated in Zion's Camp, the militia which marched to Missouri to rescue threatened church members; quarreled with Joseph Smith over finances and narrowly escaped excommunication; founded the Latter-day Saints' Millennial Starin England; married several plural wives in Nauvoo, Illinois; immigrated to the Great Salt Lake valley; and continued to fill additional overseas missions. Best known for his fiery apologetic writings such as A Voice of Warning (1837), Key to the Science of Theology (1855), and for his autobiography which was published posthumously in 1874 by his son, who wrote most of it, Pratt nevertheless defined Mormon doctrine and theology for much of the nineteenth century. He was killed in 1857 in Arkansas by the estranged husband of one of his polygamous wives. The husband, an outsider, did not share Pratt's and other Mormons' contempt for civil authority over marriage.