"God, by a sudden conversion, subdued and brought my mind to a teachable frame, which was more hardened in such matters than might have been expected from one at my early period of life. Having thus received some taste and knowledge of true godliness, I was immediately inflamed with so intense a desire to make progress therein that although I did not altogether leave off other studies, yet I pursued them with less ardour." (John Calvin, Commentary on the Book of Psalms)
John Calvin (1509-1564) was one of the most important religious figures of the last millennium and is an instantly recognizable name across the globe. An influential French theologian and pastor during the Protestant Reformation, the period when he was most active (namely during the 1530s and 1540s) was marked by increased complexity and the diffusion of the Reformation into several branches. Alongside Martin Luther, Calvin was one of the central Reformers, and after fleeing to Basel, Switzerland, he published the Institutes of the Christian Religion in 1536.
Calvin was a tireless and controversial worker who corresponded with other leading reformers of the day, but he was also a deeply theological man who published his own interpretations and teachings on scripture. Today he is chiefly remembered for the religious proponents that bear his name, as Calvinists, and their steadfast devotion to the doctrine of predestination and the absolute sovereignty of God in salvation of the human soul from death and eternal damnation.
Like Martin Luther, it has become hard to separate fact from fiction when it comes to historical accounts of Calvin, and it's just as difficult to determine what (if any) distinctions exist between the thoughts and writings of Calvin and the evolution of the Calvinists over the last four centuries.