The Oath of Leo III - by Raphael

The wall space above the window depicts a little-known but nevertheless important event in the life of Leo III, one that is supposed to have happened on the day before Charlemagne was crowned emperor. Leo III had been accused of adultery by the nephews of his predecessor Adrian I. In the presence of Charlemagne, to whom he had appealed for protection, Leo III took an oath of purgation intended to affirm his guiltlessness. In Raphael's fresco, Leo III stands at the precise center of the picture by the altar and professes his innocence with his hands resting on the Bible. In doing so, he established the argument that the pope is answerable for his deeds to God alone, creating an important basis for the spiritual and secular rule of all subsequent popes. The oath of purgation took place in front of countless high-ranking ecclesiastical and secular dignitaries, who are positioned on or at the foot of the altar steps, according to their rank. The knights in the foreground, who serve as a link with the viewers, wear contemporary costume and are therefore historically consistent with Raphael's patron Leo X, who had himself portrayed in the role of Leo III.