- Luther began developing his theological views in the early 1500s through studying the bible and discussions with other scholars. By 1517, he had come to emphasize salvation through faith alone rather than good works.
- In 1517, Luther published his 95 Theses criticizing the Catholic Church's sale of indulgences. This sparked his open challenge to the Church.
- By 1520 in several influential writings, Luther argued strongly against the authority of the Pope and Catholic Church. He said salvation comes through faith alone in Christ, not Church rituals or priests. This laid out his key beliefs that diverged from Catholic theology.