Johannes Calvin was a French theologian and reformer who played a significant role in the Protestant Reformation during the 16th century. Born in 1509, he is best known for his teachings on predestination and the sovereignty of God, which became central tenets of Calvinism. His influential work, "Institutes of the Christian Religion," laid the foundation for Reformed theology. Calvin established a theocratic government in Geneva, where he implemented strict moral codes and emphasized the importance of education and community involvement. His ideas spread throughout Europe, influencing various Protestant denominations and shaping modern Christian thought.