ON Christmas Day, 800, as Charlemagne, during the celebration of the Mass, rose from his knees before the shrine of St. Peter at Rome, the Pope placed a crown upon his head, and the Roman people saluted him with tumultuous cries: 'To Charles Augustus crowned of God, great and pacific Emperor of the Romans, long life and victory!' The scene has kindled the imagination of historians. In the ancient basilica, glowing with candlelight and jewelled vestments, the foremost warrior of Europe, conqueror of Saracens, Avars, and. Saxons, whose realm stretched from the Baltic to the Adriatic shore, from Northern Spain to the Middle Danube, seals his protective mandate over Western Christianity by the solemn ritual of Imperial Rome, and 'in the union of the Roman and the Teuton, of the memories and the civilization of the South with the fresh energy of the North . . . modern history begins'.1
It was, unquestionably, one of the most picturesque moments in the history of the Papacy, comparable only, perhaps, for dramatic effect, with that other wintry scene in the snowy, windswept courtyard of Canossa, where a suppliant Emperor waited for three days to obtain forgiveness of the Pope. Yet its significance, like that of Hildebrand's triumph, does not lie on the surface. The ceremony in St. Peter's was not a constitutional solution of the difficulties inherent in Charles's relation to the Papacy. It changed nothing in the actual situation and settled nothing for the future.2 But it is, nevertheless, as Bryce showed, the beginning of a new age, in that it determined the lines of the unending struggle between Papacy and Empire which constitutes the background of medieval European politics.
Since the days of Theodosius, when Christianity had become the official religion of the Roman Empire, no permanent reconciliation had been possible between the claims of Church and____________________