The answer is the 95 Theses.
It contained criticisms leveled against the Catholic Church and focused
on the practice of selling Indulgences.
Indulgences was a fee paid to the Church in exchange for salvation. Apart from indulgences, it also attacked other
teachings such Purgatory and the authority of the Pope. He nailed this at the Church in Wittenburg
and was willing to debate on the topic of selling indulgences. Other literary developments that contributed
to the Reformation was the translation of the Bible from Latin to German making
it easier for common people to understand and develop their own understanding
of God.
