Presbyterianism is a branch of Protestant Christianity that emphasizes the authority of Scripture and the importance of church governance by elders, known as presbyters. It originated in the 16th century during the Reformation, particularly through the teachings of John Calvin, who advocated for a system of church leadership that is representative and democratic. The core beliefs of Presbyterianism include the sovereignty of God, the necessity of grace through faith, and the priesthood of all believers. Worship services typically feature preaching, prayer, and singing, with a focus on the sermon. Presbyterians also practice two sacraments: baptism and communion.