Protestantism began in Europe with the Reformation of the 16th century. Early leaders were Jan Hus, Martin Luther and John Calvin. King Henry VIII in England led the church in his country out of communion with the Church of Rome. Although he opposed Protestant doctrines, his action in ending the Pope's role in England contributed to the advance of Protestantism under Henry's successors.
Protestant Christianity rejects the Roman Catholic belief that Christ founded the Catholic Church as his sole representative and rejects the notion that priests or saints have special access to the divine. Although Protestantism accepts that Mary gave birth to Jesus Christ while still a virgin, they reject the teaching of her perpetual virginity, and although she is greatly admired they do not elevate her to the status she holds within Catholicism.
Most Protestants stress their belief that the Bible is the inerrant Word of God, although Quakers and Pentecostals believe in personal revelation as a factor in God's connection to believers. Protestants reject the Catholic concept that Tradition—beliefs held consistently by the people of God since the time of the Apostles—is a second means (alongside Scripture) by which God reveals his will to the Church, nor do they accept Papal pronouncements as binding on all believers. With few exceptions, Protestant churches observe only two sacraments (Baptism and the Lord's Supper; on the former Protestants differ between those who baptize infants and those who baptize children and adults), not the seven sacraments that the Catholic Church accepts.
Europe was polarized by the Reformation, with most of northern Europe becoming Protestant while most of the Mediterranean regions remained loyal to the Roman Catholic Church. In the mid-sixteenth century, the Catholic Church struck back with a Counter-Reformation that is considered to be responsible for keeping such areas as Italy, France and Poland in the Catholic fold.
Religious wars broke out, the worst being the Thirty Years War (1618-1648) that devastated much of Germany and neighboring areas. By 1648 a compromise was reached such that, in the Holy Roman Empire, the religion of the Prince determined the official religion of the people. Nevertheless, religious strife continued in Germany as late as the 1870s in the Kulturkampf, and in Ireland into the late 20th century.
Each Protestant denomination launched missionary activity to spread the gospel, and they competed with each other and with Catholic missions.
The greatest successes came in the United States, where a series of revivals called the First and Second Great Awakenings resulted in many converts to various Protestant churches by 1860, and in Africa and South Korea, where Protestantism grew rapidly throughout the 20th century.
Numbers and Distribution in 1900
In terms of Europe, Due to the history of the Protestant Reformation, significant Protestant populations can be found in Denmark, Estonia, Finland, the northern part of Germany, Iceland, Latvia, Norway, Sweden, the United Kingdom, and the east, north and west of Switzerland.
In addition, one of the most striking facts in the history of Protestantism during the 19th century was its great expansion in North America. The United States by 1910 had the largest Protestant population of any land—from 65,000,000 to 66,000,000 (out of a total population of 79,000,000), which is based upon the census of 1900. Britain probably comes next with 38,000,000 Protestants (total population 42,500,000) and Germany third with somewhat more than 35,000,000 (total population 56,000,000).
According to Slate, "Protestant Christianity has been the fastest growing religion in China." Evangelical Christianity is especially growing sharply in China. See: Growth of Christianity in China
Reformed Protestantism in 1900:
- Great Britain 20,500,000
- Germany 3,000,000
- Switzerland 2,000,000
- Netherlands 3,000,000
- Hungary 2,500,000
- France 500,000
- United States 65,000,000
- Canada 2,000,000
- Australia and New Zealand 1,500,000
- India 1,500,000
- South Africa 1,000,000
- Elsewhere 2,000,000
- Total Reformed 104,500,000
Lutheran: in 1900
- Germany 32,000,000
- Norway and Sweden 7,500,000
- Denmark 2,500,000
- Finland and the Baltic Provinces 6,000,000
- Hungary 1,250,000
- United States 6,000,000
- Elsewhere 750,000
- Total Lutheran 56,000,000
Anglican: in 1900
- England 10,750,000
- Scotland and Ireland 750,000
- British Empire 4,000,000
- United States 2,500,000
- Total Anglican 24,000,000
Protestant missions 5,500,000
Grand Total in 1900: 182,000,000
Protestants made the Bible available to all persons through publication of the Scriptures in the common language and by promoting universal education. The mandatory celibacy of the clergy (including monasticism) was rejected, resulting in married clergy becoming the norm in Protestant churches. Unordained persons were permitted more voice in church affairs and in the worship services themselves.
Economic impact and impact on democratic political systems
Some historians have also contended that Protestantism played an important factor in the growth of democracy and capitalism (see also: Protestant Ethic and the Spirit of Capitalism and Protestant cultural legacies).
The Harvard University historian Niall Ferguson declared: "Through a mixture of hard work and thrift the Protestant societies of the North and West Atlantic achieved the most rapid economic growth in history."
- Martin Luther's nailing of The 95 Theses to the church door in Wittenberg on October 31, 1517. Luther became the spiritual leader of the Evangelical movement later called Lutheranism, which came to dominate much of Germany and all of Scandinavia
- King Henry VIII's asserting the independence of the English church from Papal control in 1533. Under Henry's successors, Edward VI and Elizabeth I, the English Church became Protestant, although it retained the Catholic system of governance by bishops.
- John Knox's leading of Scotland into the Presbyterian faith in 1560. He was a follower of John Calvin (and was aided by many martyrs).
Protestantism in the United States
Protestants represent the largest Christian division in the United States. There are two main groupings, the more conservative Evangelical Christians and the more liberal Mainline denominations. Some Evangelicals incline to Fundamentalism, but the terms are often used casually and inconsistently; fundamentalist groups, though strongly believing in evangelism, do not see themselves as Evangelical. Other Evangelicals are part of the Pentecostalism movement, which places emphasis on the gifts of the Holy Spirit and speaking in tongues.
There are over 200 major denominations in the United States. Among the larger groupings are:
- Episcopal (liberal)
- Pentecostal (Evangelical/charismatic)
- Holiness Movement (Evangelical)
- Seventh Day Adventist 
- United Church of Christ (liberal)
Smaller groups include:
- Protestant Ethic and the Spirit of Capitalism
- Irreligious countries with Protestant cultural legacies
- Growth of Protestantism in Russia
- Christian Union
- Bell, James S., and Tracy Macon Sumner. The Complete Idiot's Guide to the Reformation and Protestantism (2002) excerpt and text search
- Gonzalez, Justo L. A History of Christian Thought: Volume 3: From the Protestant Reformation to the Twentieth Century (1987) excerpt and text search
- Hillerbrand, Hans J. ed. The Oxford Encyclopedia of the Reformation. (OUP 1996); the book is online at many academic libraries; excerpt and text search
- Latourette, Kenneth Scott. A History of Christianity (2 vol 1975) excerpt and text search vol 1, to 1500
- Latourette, Kenneth Scott. Christianity in a Revolutionary Age: A History of Christianity in the Nineteenth and Twentieth Centuries (1958) vol 1 online edition
- Latourette, Kenneth Scott. A history of the expansion of Christianity (7 vol 1939-1970), monumental history of missionary work worldwide online edition
- MacCulloch, Diarmaid. The Reformation (2005), influential recent survey excerpt and text search
- McGonigle, Thomas D., and James F. Quigley. A History of the Christian Tradition, Vol. II: From the Reformation to the Present (1996) excerpt and text search
- New Schaff-Herzog Encyclopedia of Religious Knowledge (1911), major sources of older scholarly articles; mainline Protestant perspective
- Vol. 1: Aachen - Basilians
- Vol. 2: Basilica - Chambers
- Vol. 3: Chamier - Draendorf
- Vol. 4: Draeseke - Goa
- Vol. 5: Goar - Innocent
- Vol. 6: Innocents - Liudger
- Vol. 7: Liutprand - Moralities
- Vol. 8: Morality - Petersen
- Vol. 9: Petri - Reuchlin
- Vol. 10: Reutsch - Son
- Vol. 11: Son of Man - Tremellius
- Vol. 12: Trench - Zwingli
- Vol. 13: Index
- Ahlstrom, Sydney E. A religious history of the American people (1979) 1192 pages; classic history from broad perspective excerpt and text search
- Balmer, Randall. Protestantism in America (2005) excerpt and text search
- Balmer, Randall. Encyclopedia of Evangelicalism (2nd ed. 2004), 655pp
- Balmer, Randall. Grant Us Courage: Travels along the Mainline of American Protestantism (1996) online edition
- Hutchison, William R. ed. Between the Times: The Travail of the Protestant Establishment in America, 1900-1960 (1990) excerpt and text search
- Lippy, Charles H. and Peter W. Williams, eds. Encyclopedia of the American religious experience: studies of traditions and movements (3 vol 1988) 1872 pages; standard reference work; long essays by scholars
- Noll, Mark A. The Old Religion in a New World: The History of North American Christianity (2001) excerpt and text search, by a leading evangelical scholar
- Noll, Mark A. A history of Christianity in the United States and Canada (1992), by leading Evangelical historian excerpt and text search, by a leading evangelical scholar
- Queen, Edward L. et al., eds. Encyclopedia of American Religious History (3rd ed. 2 vol. 2009) 1200pp
- Reid, Daniel G. et al. eds., Dictionary of Christianity in America (199)
- Roof, Wade Clark, and William McKinney. American Mainline Religion: Its Changing Shape and Future (1990) excerpt and text search
- Wooley, Davis C. ed. Encyclopedia of Southern Baptists (5 vol 1958-1982); 2565 pages
- Wuthnow, Robert, and John H. Evans, eds. The Quiet Hand of God: Faith-Based Activism and the Public Role of Mainline Protestantism, (2002), 430 pp.; essays by scholars
- Placher, William C. Readings in the History of Christian Theology, Volume 2: From the Reformation to the Present (1988) excerpt and text search
- Protestantism: The fastest growing religion in the developing world, Manilla Times, 2017
- Sadly, the Awakenings also resulted in the formation of several sects which are considered in some circles to be cults, such as Seventh-Day Adventists, Christian Science, and the Mormons.
- Predominant religions, Adherence.com
- This section is based on F. Kattenbusch and Arthur C. A. Hall, "Protestantism" in New Schaff-Herzog Encyclopedia of Religious Knowledge, (1911) Vol. IX
- According to the estimate of H. K. Carroll in W. D. Grant, ed. Christendom Anno Domini 1901, (1902), i. 530–531
- H. Zeller's figures for the Eastern Church are 106,480,000, Orthodox; 8,130,000 "other [Eastern] Christians."; H. A. Krose, gives Greek Orthodox 109,000,000l schismatic Orientals, 6,554,913; Raskolniks (Russian dissenters), 2,173,371. Roman Catholics 265,000,000; Eastern Church 117,000,000.
- When Will China Become the World’s Largest Christian Country?, Slate
- In China, a church-state showdown of biblical proportions
- The Protestant Work Ethic: Alive & Well…In China By Hugh Whelchel on September 24, 2012
- However, Churches of Christ claim they are NOT Protestant, as they do not seek to reform Catholicism or any other group, only to restore Christianity to New Testament practice.
- Questions exist as to whether this group is a Christian denomination or a cult.