The unity of the Reformed Church in the United States (RCUS) consists to a large extent in its faithful adherence to a common faith and doctrine. The denomination affirms the great creeds of the early church—the Apostles’, Nicene, and Athanasian Creeds—which define historic Christianity. It also subscribes to key doctrinal statements of the Protestant Reformation—the Belgic Confession (1561), the Heidelberg Catechism (1563), and the Canons of Dort (1618–19), which together are called the Three Forms of Unity.