The Church of Jesus Christ of Latter-day Saints/The Great Apostasy
The Great Apostasy happened after the ascension of Jesus Christ. Everyone who held the priesthood was killed and those who were not killed deviated from the true teachings of Jesus Christ. The people forgot the teachings of Jesus Christ although churches existed. They differed on doctrines and many churches were founded. No church had the complete truth. This was the beginning of the Dark ages. The Dark ages only got worse with the Reformation and the translations of the Bible in the native languages of the people. Thus Martin Luther and other reformers paved the way for the restoration of the full gospel of Jesus Christ. There were many evil things done by the church in the Dark ages. For example there was the Inquisition, the crusades and heretics were burned to death.