His translation of the Bible also helped to develop a standard version of the German language and added several principles to the art of translation. Luther's hymns, best-known "A Mighty Fortress is Our God", sparked the development of congregational singing in Christianity. His marriage, on June 13, 1525, to Katharina von Bora, a former nun, began the tradition of clerical marriage within several Christian traditions.
On Halloween of 1517, Luther changed the course of human history when he nailed his 95 Theses to the church door at Wittenberg, accusing the Roman Catholic Church of heresy upon heresy. Many people cite this act as the primary starting point of the Protestant Reformation. Luther's action was in great part a response to the selling of indulgences by Johann Tetzel, a Dominican priest. Luther viewed indulgences as false and going against God's salvation. Luther believed it was faith in God's forgiveness and compassion that we achieve redemption, not through money. Luther's charges also directly challenged the position of the clergy in regard to individual salvation. Due to the recently invented printing press, Luther's 95 Thesis spread far and wide. "Within two weeks, the theses had spread throughout Germany; within two months throughout Europe. In contrast, the response of the papacy was painstakingly slow"