John Leadley Dagg (1794–1884), born in Loudoun County, Virginia, lived to be over 90 years old. He died in June 1884, as one of the most respected men in American Baptist life, and remains one of the most profound thinkers produced by his denomination. Dagg overcame extraordinary problems – a limited education, near-blindness, and physical disability – to become a great pastor in Philadelphia and elsewhere and then an educator both in Alabama and as president at Mercer University in Georgia. He was a convinced Calvinist of an evangelical kind who wrote a winsome English prose. His magnum opus, Manual of Theology (1857), was the first comprehensive systematic theology written by a Baptist in America, and it became foundationally influential for Baptists in the South.