The Oath of Purgation of Pope Leo III in 800

Two days before Charlemagne was crowned ‘Emperor of the Romans,' Pope Leo III swore an oath in order to affirm his innocence of any crimes attributed to him by his enemies. Sound reasons exist for making an assumption that there was a close relationship between these two events. Since there is no indisputable evidence in the sources concerning the motives that led to Charles' coronation, every important event prior to this act has been analyzed by historians for its potential bearing on the matter. Further, the two most important individuals, pope and king, were participants in both affairs. The hand that bore the Gospels when an oath of purification was sworn in the presence of the Frankish king was the same hand, the pope's, which placed the crown of empire on a Frankish head. Thus it has been argued that Leo gave Charlemagne the new dignity in order that the Frank might use his imperial power to chastise the papal enemies. Against this view the countering argument has been made by some historians that Leo's oath was humiliating, a fact which reduces to an absurdity the thesis that the main initiative could come from the papal Curia. Thus the oath has been considered the key to a proper evaluation of the coronation itself.