Protestantism is one of the major divisions within Christianity. It has been defined as "any of several church denominations denying the universal authority of the Pope and affirming the Reformation principles of justification by faith alone, the priesthood of all believers, and the primacy of the Bible as the only source of revealed truth" and, more broadly, to mean Christianity outside "of an Orthodox or Catholic church". It is a movement that is widely seen as beginning in Germany with The Ninety-Five Theses in 1517 as a reaction against medieval doctrines and practices, especially in regard to salvation, justification, and ecclesiology. The doctrines of the over 33,000 Protestant denominations vary, but most include justification by grace through faith alone, known as Sola Gratia and Sola Fide respectively, the priesthood of all believers, and the Bible as the supreme authority in matters of faith and morals, known as Sola Scriptura, Latin for "by scripture alone".
In the 16th century, the followers of Martin Luther established the evangelical (Lutheran) churches of Germany and Scandinavia. Reformed churches in Hungary, Scotland, Switzerland and France were established by other reformers such as John Calvin, Huldrych Zwingli, and John Knox. The Church of England declared independence from papal authority in 1534, and was influenced by some Reformation principles, notably during the English Civil War. There were also reformation movements throughout continental Europe known as the Radical Reformation which gave rise to the Anabaptist, Moravian, and other pietistic movements.
The exact origin of the term protestant is unsure, and may come either from French protestant or German Protestant. However, it is certain that both languages derived their word from the Latin: protestantem, meaning "one who publicly declares/protests", which refers to the letter of protestation by Lutheran princes against the decision of the Diet of Speyer in 1529, which reaffirmed the edict of the Diet of Worms in 1521, banning Martin Luther's 95 theses of protest against some beliefs and practices of the early 16th century Catholic Church.
The term Protestant was not initially applied to the Reformers, but later was used to describe all groups protesting Roman Catholic orthodoxy. Since that time, the term Protestant has been used in many different senses, often as a general term merely to signify Christians who belong to none of the Churches of Catholic tradition (Roman, Orthodox, Monophysite or Nestorian Churches).
In 1517, Martin Luther, a German Augustinian friar, published the 95 theses. Popular history holds that these theses were nailed to a church door in the university town of Wittenberg by Luther himself, but this claim has recently come under scrutiny (see article on Martin Luther for discussion). Luther's propositions challenged some portions of Roman Catholic doctrine and a number of specific practices.