John Calvin (1509–1564) was a French theologian, pastor, and reformer during the Protestant Reformation. Born in Noyon, France, he initially studied law but shifted to theology after experiencing a religious conversion around 1533. Calvin became a leading figure in the development of Reformed theology, emphasizing the sovereignty of God, the authority of Scripture, and the doctrine of predestination. His most influential work, Institutes of the Christian Religion, first published in 1536, systematically presented Protestant beliefs and became a foundational text for Reformed churches. In 1536, Calvin settled in Geneva, Switzerland, where he implemented extensive church reforms and helped establish a theocratic government. Calvin’s teachings gave rise to Calvinism, which significantly influenced the development of Protestant denominations like the Presbyterian and Reformed churches. He died in Geneva in 1564, leaving a lasting legacy in theology, education, and church governance.