John Calvin (or Jean Calvin) (10 July 1509 - 27 May 1564) was a French Protestant theologian during the Protestant Reformation and was a central developer of the system of Christian theology called Calvinism or Reformed theology. In Geneva, his ministry both attracted other Protestant refugees and over time made that city a major force in the spread of Reformed theology. He is famous for his teachings and writings, in particular for his Institutes of the Christian Religion.