212 THE HISTORY OF MEDIEVAL EUROPE backward rather than forward. His octagonal cathedral at Charle- Aachen, which is still standing, copied the plan m ia gne in °f San Vitale at Ravenna and imported columns history f r0 m Ravenna, Treves, and Rome for its interior decoration — a task to which contemporary artists were y/cloubtless unequal. He did not try to alter much the crude economic conditions of his age, and he probably never dreamt of social reform. His coronation as Roman emperor seems a political retrospect rather than an advance toward the modern type of state. He showed little consideration for what is to-day called the spirit of nationality ; he forced Lombards and Bavarians and Saxons and Spaniards under his autocratic rule, and then was ready to divide arbitrarily among his descendants the briefly realized unity of his em- pire. We shall see that the decline of his empire, more than its creation, marked a transition toward modern history, and that his inability to subdue the Northmen and the Arabs hastened that day more than did his conquest of the Saxons. While the conception of imperial Rome was to endure and another attempt to realize it was to be made later, Charle- Disintegra- magne's empire began to disintegrate, directly Frankish e n * s commanding personality disappeared. It was Empire on i y an accident that its unity was preserved when he died. He had planned in accordance with Frank- ish custom to divide among his three sons the territories which he had been at such pains to unite ; but only one son survived him, Louis the Pious, and ruled alone as emperor from 814. Louis's sons kept pestering him to partition his realm among them and he did so several times before his death. As early as 817 he made Lothair his associate in the imperial office; gave to Pepin, Aquitaine; to Louis, Bavaria; and to a nephew, Italy. In 829 Charles received Alamannia. In 833 the sons tried to get rid of their father, who was too gentle for that age, by shutting him up in a monastery, but he recovered the throne and lived on until 840. Meanwhile Pepin had died and there had been new divisions of territory and more revolts. Lothair succeeded his father as emperor,
