John Leadley Dagg (1794–1884) born in Loudoun County, Virginia, lived to be over 90 years old. He died in June of 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 being crippled – 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.
As an educator and theologian, Dagg is best known for his work in Georgia between 1844 and 1870. From 1844 to 1856 he was on the faculty of Mercer University, then located in Penfield, as professor of theology and later president of the college.
His greatest contribution to Baptist life came after his retirement in 1856. He prepared A Manual of Theology (1857), the first systematic theology by a Baptist in America, A Treatise on Church Order (1858), The Elements of Moral Science (1859), and The Evidences of Christianity (1869). His reputation as a theologian and ethicist rests on these four works. The first two are still in print.