diametrically opposed to the cooperation between works and grace, a cornerstone of medieval theology. As a priest, he was seriously interested in the reform of the church; he was especially disturbed by practices surrounding indulgences, which claimed to wipe out sins through good works and even through monetary payments. On October 31, 1517, he posted a series of ninety-five propositions in Latin critical of indulgences, which he wished to defend in academic theological debate. However Luther initially