The "Institutes of the Christian Religion" is a foundational theological work written by the Protestant reformer John Calvin in the 16th century. It systematically outlines Calvin's beliefs about Christian doctrine, emphasizing the sovereignty of God, the authority of Scripture, and the necessity of grace for salvation. The text played a significant role in the development of Reformed theology and the Protestant Reformation. First published in 1536, the "Institutes" underwent several revisions and expansions throughout Calvin's life. It serves as both a guide for understanding Christian faith and a defense against opposing views, influencing many Protestant denominations and shaping the course of Western Christianity.