Both theologians found in the mediæval doctrine of the Sacrament of the Supper what they believed to be an overwhelming error destructive to the spiritual life. It presupposed that a priest, in virtue of mysterious powers conferred in ordination, could give or withhold from the Christian people the benefits conveyed in the Sacrament. It asserted that the priest could change the elements Bread and Wine into the very Body and Blood of Christ, and that unless this change was made there was no presence of Christ in the sacrament, and no possibility of sacramental grace for the communicant. Luther attacked the problem as a mediæval Christian, content, if he was able to purge the ordinance of this one fault, to leave all else as he found it. Zwingli came as a Humanist, whose fundamental rule was to get beyond the mediæval theology altogether, and attempt to discover how the earlier Church Fathers could aid him to solve the problem. This difference in mental attitude led them to approach the subject from separate sides; and the mediæval way of looking at the whole subject rendered difference of approach very easy. The mediæval Church had divided the Sacrament of the Lord’s Supper into two distinct parts—the Mass and the Eucharist.(332) The Mass was inseparably connected with the thought of the great Sacrifice of Christ upon the Cross, and the Eucharist with the thought of the believer’s communion with the Risen Living Christ. Zwingli attacked the Romanist doctrine of the Mass, and Luther sought to give an evangelical meaning to the mediæval conception of the Eucharist. Hence the two Protestant antagonists were never exactly facing each other. Luther’s convent studies in D’Ailly, Biel, and their common master, William of Occam, enabled him to show that there might be the presence of the Glorified Body of Christ, extended in space, in the elements Bread and Wine in a natural way, and without any priestly miracle: and that satisfied him; it enabled him to deny the priestly miracle and keep true in the most literal way to the words of the institution, “This is My Body.” Zwingli, on the other hand, insisted that the primary reference in the Lord’s Supper was to the death of Christ, and that it was above all things a commemorative rite. He transformed the mediæval Mass into an evangelical sacrament, by placing the idea of commemoration where the mediæval theologian had put that of repetition, and held that the means of appropriation was faith and not eating with the mouth. This he held to be a return to the belief of the early centuries, before the conception of the sacrament had been corrupted by pagan ideas.