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".