Protestantism is a form of Christianity which originated with the Reformation, a movement against what its followers considered to be errors in the Roman Catholic Church. It is one of the three major divisions of Christendom, together with Roman Catholicism and Orthodoxy. The term derives from the letter of protestation from German Lutheran princes in 1529 against an edict of the Diet of Speyer condemning the teachings of Martin Luther as heretical.
With its origins in Germany, the modern movement is popularly considered to have begun in 1517 when Luther published his Ninety-five Theses as a reaction against abuses in the sale of indulgences, which purported to offer remission of sin to their purchasers. Although there were earlier breaks from or attempts to reform the Roman Catholic Church—notably by Peter Waldo, John Wycliffe, and Jan Hus—only Luther succeeded in sparking a wider, lasting movement.
Protestants reject the notion of papal supremacy and deny the Roman Catholic doctrine of transubstantiation, but disagree among themselves regarding the real presence of Christ in the Eucharist. They emphasize the priesthood of all believers, the doctrine of justification by faith alone (sola fide) rather than by or with good works, and a belief in the Bible alone (rather than with sacred tradition) as the highest authority in matters of faith and morals (sola scriptura). The "Five solae" summarize the reformers' basic differences in theological beliefs and opposition to the teaching of the Roman Catholic Church.