The German Reformation was a religious movement in the 16th century that aimed to reform the practices and beliefs of the Roman Catholic Church. It began in 1517 when Martin Luther, a German monk, published his Ninety-Five Theses, criticizing the Church's sale of indulgences and other practices he viewed as corrupt. This sparked widespread debate and led to the formation of various Protestant denominations. As the movement gained momentum, it resulted in significant political and social changes across Europe. The Peace of Augsburg in 1555 allowed rulers to choose between Catholicism and Lutheranism for their territories, marking a crucial step in the establishment of religious pluralism in Germany.