Presbyterianism is a form of Christianity that broke from the Roman Catholic Church during the 16th-century Protestant Reformation. Presbyterian churches derive their name from the presbyterian form of church government by representative assemblies of elders. Presbyterians believe in the sovereignty of God, the authority of the Scriptures, and the necessity of grace through faith in Christ. Presbyterian church governance is ensured by representative assemblies of elders, and the Presbyterian Church is governed by two types of elders: ruling elders and teaching elders. Presbyterian theology is historically a confessional tradition, and Presbyterians believe that the Scriptures of the Old and New Testaments are the Word of God and the only infallible rule of faith and practice. Presbyterians believe in the sacraments of baptism and the Lords Supper, and they believe that God instituted these two sacraments as a sign of the power of Christ. Presbyterians are distinctive in two major ways: they adhere to a pattern of religious thought known as Reformed theology and a form of government that stresses the active, representational leadership of both ministers and church members.