A major contributor to Reformed theology was John Calvin, who converted from Roman Catholicism after training for the priesthood and in the law. In exile in Geneva, Switzerland, Calvin developed the presbyterian pattern of church government, which vests governing authority primarily in elected laypersons known as elders. The word presbyterian comes from the Greek word for elder.
Elders are chosen by the people. Together with ministers of the Word and Sacrament, they exercise leadership, government, and discipline and have responsibilities for the life of a particular church as well as the church at large, including ecumenical relationships. They shall serve faithfully as members of the session. (Book of Order, G-10.0102) When elected commissioners to higher governing bodies, elders participate and vote with the same authority as ministers of the Word and Sacrament, and they are eligible for any office (Book of Order G-6.0302).