Martin Luther was a German theologian, philosopher, and leader of the Protestant Reformation whose ideas changed the course of history. His 95 Theses, nailed to the door of the Wittenberg Castle Church, sparked a movement that led to religious, social, and political upheaval across Europe. Luther's courage in challenging the established norms of the Catholic Church and his emphasis on the importance of personal faith and scripture resonated deeply with many. His legacy is one of transformation, showing that one individual's conviction can ignite lasting change and inspire millions to stand for truth.