This is Luther's direct letter and treatise to Pope Leo X on his religious beliefs and a bruising analysis of the Catholic church. Luther strongly objected to making a new law of the forms and urged the retention of other good liturgies. While advocating Christian liberty in liturgical matters, he also spoke out in favor of maintaining and establishing liturgical uniformity among those sharing the same faith in a given area. "Concerning Christian Liberty" is a wonderful piece on Luther's balance between the Catholic Church and his teachings on liberty.