John Calvin
French theologian, jurist and reformer (1509–1564), born in Noyon, Picardy, trained in law and the humanities at Paris, Orléans and Bourges before his conversion to Protestantism around 1533, which forced him to flee France and eventually brought him to Geneva, a city he governed de facto on the spiritual and moral plane until his death and which he turned into the international centre of Reformed Protestantism. His masterwork, the Institutes of the Christian Religion, first published in 1536 at the age of twenty-six and expanded and revised throughout his life until the definitive 1559 edition, is the most influential systematic summa of Protestant theology: in it, with rigorous logic and remarkably clear Latin (and later French), he expounds the doctrine of predestination —God has decided from eternity, immutably, who will be saved and who condemned, independently of human merit—, the absolute sovereignty of God over all creation and history, the total corruption of human nature through original sin, and the supreme authority of Scripture above ecclesiastical tradition and papal magisterium. In Geneva he established a theocratic regime of strict moral discipline, with a consistory that monitored the public and private conduct of citizens and could impose excommunication, and he was directly involved in the execution for heresy of Michael Servetus in 1553, an episode that has heavily marked his historical reputation despite his modern defenders. The resulting Calvinism —with its ethic of work, thrift and earthly vocation as a form of divine service, which Max Weber would later link to the origins of modern capitalism— spread to Scotland (through John Knox), the Netherlands, parts of France (the brutally persecuted Huguenots), and later to New England through the Puritans, shaping one of the most influential and enduring branches of worldwide Protestantism.