Cotton was the oldest of nine children of Increase Mather, pastor of North Church, Boston. Increase and his three brothers were all Puritan ministers in England; one was an independent. Cotton’s father preached for fifty years, to fifteen hundred souls, most Sundays. Cotton entered Harvard at age 12 and mastered Greek, Hebrew and Latin. In time he assisted his father and eventually replaced him as pastor.
Cotton Mather worked an average of sixteen hours per day, not counting the occasional all-night prayer vigils. Unlike his father, Cotton put great energy into pastoral ministry — visiting the sick, catechizing the church children (and his own fifteen!); he led Bible studies and counseled. By the end of his life he could count more than four-hundred published works, including sermons, catechisms, translations and creeds for Indians, medical guides, biographies, histories, scientific works, and ministerial advice. He admired his father and grandfathers almost to idolatry and deferred to his father even when he disagreed with him. An avid reader like his forbears, he added to the Mather family library which totaled more than seven thousand volumes, the largest private library in the colonies — larger than Harvard’s.