Presbyterian and Reformed churches both trace their heritage back to the 16th century C.E. and the reformer John Calvin. Calvin's writings formed much of what is still the basis of both Presbyterian and Reformed religious thought. Calvin did most of his writing from Geneva, Switzerland, and from there the Reformed movement spread throughout Europe. The Presbyterian Church traces much of its history from England and Scotland, where John Knox brought Reformed thinking. Presbyterian and Reformed Churches maintain much of the basic Protestant doctrine, but are distinct for their adherence to Reformed theology and their unique structure of church government, which stresses leadership representation by both church congregants and ministers. Presbyterians get their name from this presbyterian form of structure, which grants authority to elected lay leadership. These lay leaders, called elders or presbyters, partner with ordained ministers to govern congregations. In this, Reformed traditions have two forms of governance: Presbyterian polity (rule by ordained assemblies) and Congregationalist polity (rule by leaders within the congregation). Reformed theology stresses the majesty and holiness of God expressed as love through the creation and redemption of the world. This is related to the Reformed theology of election (also called predestination), which claims that God elects the people of God for salvation. Reformed doctrine also places high authority on scripture as the primary source of instruction regarding faith and practice. Presbyterian and Reformed churches have both gone through numerous periods of splits and reunifications, and have spread throughout the world primarily through missionary activity and migration.