Protestantism is a form of Christian faith and practice which originated with the Protestant 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 Eastern Orthodoxy.Anglicanism is sometimes considered to be independent from Protestantism. The term derives from the letter of protestation from Lutheran princes in 1529 against an edict 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 The 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, Arnold of Brescia,Girolamo Savonarola, John Wycliffe, and Jan Hus—only Luther succeeded in sparking a wider, lasting movement.