The Institutes, formally known as 'Institutes of the Christian Religion,' is a foundational theological work by John Calvin, first published in 1536. This text laid out Calvin's doctrine of Protestantism, emphasizing concepts like predestination and the sovereignty of God, and played a crucial role in shaping Reformed theology during the Reformation period. Its influence extended into the Wars of Religion, as Calvinism became a major theological force that shaped conflicts between Catholic and Protestant factions across Europe.