Protestantism is a form of Christianity that originated in the Protestant Reformation. It emphasizes justification of sinners through faith alone, the teaching that salvation comes by unmerited divine grace, the priesthood of all believers, and the Bible as the sole infallible source of authority for Christian faith and practice. The five solæ summarize the basic theological beliefs of mainstream Protestantism.
Protestants follow the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies.Löffler, K. (1910), Pope Leo X , The Catholic Encyclopedia, New York: Robert Appleton Company, "The immediate cause was bound up with the odious greed for money displayed by the Roman Curia, and shows how far short all efforts at reform had hitherto fallen...Abuses occurred during the preaching of the Indulgence. The money contributions, a mere accessory, were frequently the chief object, and the "Indulgences for the Dead" became a vehicle of inadmissible teachings...(The pope) gave himself up unrestrainedly to his pleasures and failed to grasp fully the duties of his high office." The Reformation began in the Holy Roman Empire in 1517, when Martin Luther published his Ninety-five Theses as a reaction against abuses in the sale of indulgences by the Catholic Church, which purported to offer the remission of the temporal punishment of sins to their purchasers. Luther's statements questioned the Catholic Church's role as negotiator between people and God, especially when it came to the indulgence arrangement, which in part granted people the power to purchase a certificate of pardon for the penalization of their sins. Luther argued against the practice of buying or earning forgiveness, claiming instead that salvation is a gift God gives to those who have faith.
Lutheranism spread from Germany into Denmark–Norway, Sweden, Finland, Livonia, and Iceland. Calvinist churches spread in Germany, Hungary, the Netherlands, Scotland, Switzerland, France, Poland and Lithuania, led by Protestant Reformers such as John Calvin, Huldrych Zwingli and John Knox. The political separation of the Church of England from the Catholic Church under King Henry VIII began Anglicanism, bringing England and Wales into this broad Reformation movement, under the leadership of reformer Thomas Cranmer, whose work forged Anglican doctrine and identity.
Protestantism is divided into various denominations on the basis of theology and ecclesiology. Protestants adhere to the concept of an invisible church, in contrast to the Catholic, the Eastern Orthodox Church, the Oriental Orthodox Churches, the Assyrian Church of the East, and the Ancient Church of the East, which all understand themselves as the only original church—the "one true church"—founded by Jesus Christ (though certain Protestant denominations, including historic Lutheranism, hold to this position).Heussi, Karl (1956). Kompendium der Kirchengeschichte, 11., Tübingen (Germany), pp. 317–319, 325–326 A majority of Protestants are members of a handful of Protestant denominational families; Anglicans/Episcopalians, Baptists, Calvinist/Reformed, Lutherans, Methodists and Moravians. Furthermore, Adventists, Pentecostals, Quakers, Plymouth Brethren, independent churches also known as Nondenominational Christianity, and Charismatic Christianity can also be considered part of Protestantism broadly speaking. Independent/Non-Denominational churches are on the rise, having recently expanded rapidly throughout much of the world.World Council of Churches: Evangelical churches : "Evangelical churches have grown exponentially in the second half of the 20th century and continue to show great vitality, especially in the global South. This resurgence may in part be explained by the phenomenal growth of Pentecostalism and the emergence of the charismatic movement, which are closely associated with evangelicalism. However, there can be no doubt that the evangelical tradition "per se" has become one of the major components of world Christianity. Evangelicals also constitute sizable minorities in the traditional Protestant and Anglican churches. In regions like Africa and Latin America, the boundaries between "evangelical" and "mainline" are rapidly changing and giving way to new ecclesial realities."Christian Traditions, Pew Research Center, 2011, "The third group broadly defined as Protestants in this report is independent Christians. Independent Christians have developed ecclesial structures, beliefs and practices that are claimed to be independent of historic, organized Christianity.10 Independent Christians include denominations in sub-Saharan Africa that identify as independent from historically Protestant denominations, churches in China that are not affiliated with official religious associations and nondenominational churches in the United States."Anckar, Carsten (2022), Religion and Democracy: A Worldwide Comparison, p103, "Wide definition of Protestantism...includes Protestants, Marginal Christians, Anglicans, Christian Independents, and unaffiliated Christians"Johnstone, Patrick, The Future of the Global Church: History，Trends and Possibilities, p115 These various movements, collectively labeled "popular Protestantism" by scholars such as Peter L. Berger, have been called one of the contemporary world's most dynamic religious movements.
Historically speaking however, Protestantism includes only the denominations that emerged directly during the Protestant Reformation, thus excluding any denomination that emerged after this period. In 2004, Hans Hillerbrand estimated a total Protestant population of 833,457,000, while the World Christian Database estimated 637,856,000 Protestants and 426,370,000 Independents (mostly non-denominational Pentecostals who do not self-identify as Protestants) in early 2026.
Terminology
Six princes of the Holy Roman Empire and rulers of fourteen Imperial Free Cities, who issued a protest (or dissent) against the edict of the Diet of Speyer (1529), were the first individuals to be called Protestants. The term protestant, though initially purely political in nature, later acquired a broader sense, referring to a member of any Western church which subscribed to the main Protestant principles. A Protestant is an adherent of any of those Christian bodies that separated from the Church of Rome during the Reformation, or of any group descended from them.
During the Reformation, the term protestant was hardly used outside of German politics. People who were involved in the religious movement used the word evangelical (). Gradually, protestant became a general term, meaning any adherent of the Reformation in the German-speaking area. It was ultimately somewhat taken up by Lutherans, even though Martin Luther himself insisted on Christian or evangelical as the only acceptable names for individuals who professed faith in Christ. French and Swiss Protestants instead preferred the word reformed, which became a popular, neutral, and alternative name for Calvinists.
The word evangelical, which refers to the gospel, was widely used for those involved in the religious movement in the German-speaking area beginning in 1517. Evangelical is still preferred among some of the historical Protestant denominations in the Lutheran, Calvinist, and United (Lutheran and Reformed) Protestant traditions in Europe, and those with strong ties to them. Above all the term is used by Protestant bodies in the German-speaking area, such as the Protestant Church in Germany. Thus, the German word means Protestant, while the German , refers to churches shaped by Evangelicalism. The English word evangelical usually refers to evangelical Protestant churches, and therefore to a certain part of Protestantism rather than to Protestantism as a whole. The English word traces its roots back to the Puritans in England, where Evangelicalism originated, and then was brought to the United States.
Martin Luther always disliked the term Lutheran, preferring the term evangelical, which was derived from euangelion, a Greek word meaning "good news" (i.e. "gospel").Espín, Orlando O. and Nickoloff, James B. An introductory dictionary of theology and religious studies. Collegeville, Minnesota: Liturgical Press, p. 796. The followers of John Calvin, Huldrych Zwingli, and other theologians linked to the Reformed tradition, also began to use that term. To distinguish the two evangelical groups, others began to refer to the two groups as Evangelical Lutheran and Evangelical Reformed. Lutherans themselves began to use the term Lutheran in the middle of the 16th century, in order to distinguish themselves from other groups such as the Philippists and Calvinists.
The German word , which roughly translates to English as "reformational" or "reforming", is used as an alternative for in German, and is different from English reformed (), which refers to churches shaped by ideas of John Calvin, Huldrych Zwingli, and other Reformed theologians. Derived from the word "Reformation", the term emerged around the same time as Evangelical (1517) and Protestant (1529).
Theology
Many experts have proposed criteria to determine whether a Christian denomination should be considered part of Protestantism. A common consensus approved by most of them is that if a Christian denomination is to be considered Protestant, it must acknowledge the following three fundamental principles of Protestantism. Sola Scriptura
The belief, emphasized by Luther, in the Bible as the highest source of authority for the church. The early churches of the Reformation believed in a critical, yet serious, reading of scripture and holding the Bible as a source of authority higher than that of tradition, though Lutherans cherish tradition for its role in maintaining order and transmitting the Gospel. The many abuses that had occurred in the Western Church before the Protestant Reformation led the Reformers to reject certain Roman Catholic traditions. In the early 20th century, a less critical reading of the Bible developed in the United States—leading to a "fundamentalist" reading of Scripture. Christian fundamentalists read the Bible as the "inerrant, infallible" Word of God, as do the Catholic, Eastern Orthodox, Lutheran and Anglican churches, but interpret it in a literalist fashion without using the historical-critical method. Methodists and Anglicans differ from Lutherans and the Reformed on this doctrine as they teach prima scriptura, which holds that Scripture is the primary source for Christian doctrine, but that "tradition, experience, and reason" can nurture the Christian religion as long as they are in harmony with the Bible (Protestant canon).
Quakers and Methodists (inclusive of the holiness movement), as well as Radical Pietists, Pentecostals and Spiritual Christians emphasize the Holy Spirit and personal closeness to God.Woodhead, Linda. Christianity: A Very Short Introduction (Oxford University Press, 2014). pp. 57–70.
There was also a time when scripture became the new religious imagery. Reformed (Calvinist) theology drew out iconoclastic events when John Calvin arrived in Geneva in 1536. Calvin inherited a city where the old medieval Christian world, with its rituals, images, and pilgrims were taken apart. After the events of the iconoclasm in 1566, scripture began to take place of the religious images that were previously removed. These new text images turned scripture into a visual tool. The absence of traditional images created room for the joint idea of scripture with visual objects, generating a new imagery culture that focused on reading, understanding, and reflecting over observations.
Justification by faith alone