When Gratian’s Decretum took its final shape in the mid-twelfth century, one of its three major parts, the Tractatus de consecratione ecclesiae, focused on sacramental law. De consecratione, added in the second recension, reflects the theological climate of the time, when theologians defined seven sacraments: baptism, confirmation, penance, the Eucharist, holy orders, matrimony, and extreme unction. Previously, the sacraments had occupied only a modest place in the canon law, with exceptions like the Decretum of Burchard of Worms and the collections ascribed to Ivo of Chartres. De consecratione was divided into five distinctions, focused on churches, the Eucharist, and baptism. The text exposed students to the concept of the Real Presence of Christ in the consecrated bread and wine, reflecting the theologies of the previous century and the Gregorian Reform’s critique of simony, buying and selling spiritual gifts.

The French religious universe of John Calvin’s youth was complex and powerful. Calvin retained and strengthened many of its central beliefs and practices. Others he modified and realigned to reflect his understanding of an authentic scripturally based Christianity. Finally, Calvin emphatically rejected and sought to suppress a third group of religious views and behaviors that he regarded as unfounded, superstitious, and, in some instances, dangerously idolatrous. Whatever Calvin’s assessment, late medieval religious practices and the beliefs that undergirded them were elaborate and pervasive. They held great appeal for a substantial number of people from all social strata, extending from the broad oral culture of the unlettered majority to the elite ranks of the learned and privileged.