John Calvin is one of the most recognized names among the reformers, and for good reason. Calvinism is named after this theologian and the Reformed Churches have the doctrines that he espoused at their core. Though there are several similarities between Reformed Churches and Lutheranism, there are significant differences too. Reformed Churches gained support in Switzerland, France, the Netherlands, England, and Scotland. Today, the Reformed Churches include Continental Reformed Protestantism, Presbyterianism, Evangelical Anglicans, Congregationalists, and Reformed Baptists.
Origins of the Reformed Churches

The Reformed Churches, much like the Lutheran Church, are a product of the Reformation. They trace their origins to reformers like Martin Bucer, Heinrich Bullinger, John Calvin, and Ulrich Zwingli.
Different parts of Switzerland predominantly spoke German, French, or Italian, as they do today. Ulrich Zwingli and Bullinger, who were German-speaking reformers, taught in Zurich in the Northeast of Switzerland and tended to engage with the Lutheran movement more than others.
Zwingli traveled to Marburg Castle to meet with Martin Luther at the Colloquy of Marburg from the 1st to the 4th of October, 1529. They hoped to find common ground that would allow them to establish a loose alliance as co-reformers against Catholic forces, and to unify in spreading the Protestant message.

Their differences in view on Communion prevented such ambitions. Ulrich Zwingli claimed that in Communion, the bread and wine were purely symbolic and served as a memorial to Christ’s death. Martin Luther insisted that Christ was present “in, with, and under” the bread and wine, quoting the synoptic gospels by saying: “This is my body.” The inability to find common ground on the Eucharist resulted in a tearful response from Zwingli who passionately desired unity among the reformers. Luther’s harsh response on the matter softened significantly as time went by, as is evident in his later reflections on it.
Shortly thereafter, on October 11, 1531, Zwingli died in the Second War of Kappel when Catholic forces came to retake Zurich. He had been followed as leader of the Reformation in the city by Bullinger; reformers in Zurich became increasingly hesitant to engage with the Lutheran line on the Reformation.
Calvin had to flee France and settle in Geneva, Switzerland, where he became a notable Reformed preacher, teacher, and scholar. He joined forces with other reformers like Guillaume Farel and worked toward bringing a purer version of biblical teaching to the people. Though this part of Switzerland was predominantly French-speaking, they continued to reach out to Martin Luther, and after his death, to Philip Melanchthon, attempting to win them to their views.

Calvin preached Reformation principles and, informed by his excellent mastery of Greek and Hebrew, explained what the Bible teaches. He exposed the principles the Catholic Church espoused that did not align with the Bible and he authored commentaries on most books of the Bible to make its content accessible and understandable by anyone who read it. The first edition of Institutes of the Christian Religion saw the light in 1536. This masterful work defended the doctrinal position of the reformers, discussing themes like the sovereignty of God, human depravity and grace, predestination, the role of Scripture, the Church and the sacraments, and the Christian Life.
The need for collaboration among different Reformed movements was clear. In 1549, Calvin and Bullinger drew up the Consensus Tigurinus (Consensus of Zurich) which represented a view between Luther’s belief in the real presence of Jesus in Communion and Zwingli’s symbolic view. It paved the way for collaboration between reformers even though they did not agree on every detail. This is a feature of the Reformed Churches to this day. Different expressions of faith share a common core, though small details may not exactly align. The differences between Reformed Churches have resulted in various cultures and practices, though they essentially remain unified on core convictions.
Though Calvinism carries Calvin’s name, Calvinism developed during the century-and-a-half after his death. Calvin’s views are, therefore, not synonymous with Calvinism. It is part of Reformed theology, though Reformed theology is a much broader concept that details aspects of faith Calvin did not address.
General Beliefs

In many ways, Reformed Churches share the beliefs of the Lutherans. Both believe in Sola Scriptura, Sola Gratia, and Sola Fide: the Bible alone is the rule and standard for Christian belief and conduct, believers are saved by grace (unmerited favor) alone, and faith alone saves with no work on the part of the believer having merit toward salvation. Belief in the Trinity: God the Father, God the Son, and God the Holy Spirit is also well established in both traditions.
Lutherans and Reformed Christians believe in the priesthood of all believers and practice two sacraments: Baptism and Communion (the Lord’s Supper). Both reject the Catholic view of Transubstantiation, which is the belief that the bread and wine literally turn into the flesh and blood of Christ. They also share the belief that original and personal sins are washed away by the cross and that no earthly mediator, like a priest in Catholicism, is necessary when praying to God.
Calvinism teaches predestination and election which is summarized by the acronym TULIP:
Total depravity: Humans are lost in sin and cannot choose God on their own.
Unconditional Election: God elects certain people regardless of their condition.
Limited Atonement: Christ’s atonement was sufficient for all but only affected the elect.
Irresistible Grace: Those called by Christ cannot resist the grace they received.
Perseverance of the Saints: The elect cannot permanently fall away.

The Foundational Reformed Confessions consist of The Heidelberg Catechism, The Belgic Confession, The Canons of Dort, and The Belhar Confession. The Heidelberg Catechism explains the significance of the gospel, the sacraments, the Ten Commandments, and the Lord’s Prayer in Reformed terms. The Belgic Confession details the beliefs of the Christian faith, highlighting its Reformed aspects. The Canons of Dort, which detailed the TULIP acronym, focuses on the Reformed teaching of salvation and God’s grace. The Belhar Confession argues for unity, reconciliation, and justice.
Distinct Beliefs

Reformed Churches differ from other denominations in several ways. They focus on the glory of God, whereas Lutherans focus on the theology of the cross. Calvin did not share Luther’s belief that Jesus was physically present in Communion, opting to recognize his spiritual presence through the Holy Spirit. He also did not share Zwingli’s view that Communion is man’s own doing in remembrance of Christ’s death, rather considering Jesus the host that gives the grace to take part in the practice. Calvin believed the civil government was a necessary agent of God and had to not only be obeyed but actively supported.
Reformed theology views the Bible from a covenant perspective. Initially, there was a covenant of works with Adam, which failed due to Adam’s disobedience. Several covenants of grace between God and his elect followed. These covenants include the Noahic Covenant which saw God save Noah and his family; the Abrahamic Covenant with circumcision as its sign; the Mosaic Covenant which featured the Ten Commandments; the Davidic Covenant which saw the promise that his descendants would rule forever and was fulfilled in Christ; and the New Covenant, which transcends the earlier covenants and is characterized by the outpouring of the Holy Spirit and the Law of God being imprinted on the hearts of all believers.
Reformed Churches believe the covenants of grace are connected, which would explain why there is so much continuity between the Old Testament and New Testament, and why the New Testament often refers to the Old Testament and the covenants it details. Rather than one covenant replacing another, Reformed theology teaches that one builds on the previous to highlight the overarching covenant between God and man.
Structure

Due to the variety of churches that are Reformed Churches, their structures vary. In the Presbyterian tradition, pastors of local churches and some elders make up a presbytery that governs a district. Several presbyteries constitute a synod, and elected members may represent them at a General Assembly. The World Communion of Reformed Churches is one notable international body for Reformed Churches.
In Congregational Churches, the model of governance is more decentralized. These congregations are independent though they form councils or associations for mutual support, joint mission, or to address common concerns. The councils or associations have no binding authority over constituent congregations.
Some Congregational Churches follow a hybrid model of governance that incorporates some of the Presbyterian elements of governance. Local congregations must give final approval before decisions are implemented.
Regardless of the greater governance model, local churches tend to have three levels of offices in the local church. Firstly, the pastor, minister, or teaching elder is an ordained leader authorized to preach, teach, and administer sacraments. Secondly, lay leaders are elected as elders to assist the pastor in spiritual care and oversight of the congregation. Thirdly, deacons are appointed to perform tasks of caring, managing, and maintaining resources and assets.