改革宗, or the Reformed tradition, is a branch of Protestant Christianity that emerged in the 16th century during the Reformation. It emphasizes the sovereignty of God, the authority of Scripture, and the necessity of grace through faith. Key figures in this movement include John Calvin and Huldrych Zwingli, who contributed to its theological foundations. The Reformed tradition is characterized by its distinct beliefs about salvation, predestination, and the sacraments. It has influenced various denominations, including the Presbyterian and Reformed churches. The movement continues to impact Christian thought and practice around the world today.