35. It was a matter of great importance to the world whether Charlemagne's extensive empire was, after his death, to remain one or to fall apart. He himself appears to have had no expectation that it would hold together, for in 806 he divided it up in a very arbitrary manner among his three sons. We do not know whether he was led thus to undo his life's work simply because the older tradition of a division among the king's sons was as yet too strong to permit him to hand down all his possessions to his eldest son, or because he believed it would be impossible to keep together so vast and heterogeneous a realm. However this may have been, the death of his two eldest sons left only Louis, who succeeded his father both as king and emperor. [Sidenote: Partition of Charlemagne's empire among the sons of Louis the Pious.] Louis the Pious had been on the throne but a few years before he took up the all-important problem of determining what share each of his sons should have in the empire after his death. As they were far too ambitious to submit to the will of their father, we find no less than six different partitions between the years 817 and 840. We cannot stop to trace these complicated and transient arrangements, or the rebellions of the undutiful sons, who set the worst possible example to the ambitious and disorderly nobles. On the death of Louis the Pious, in 840, his second son, Louis the German, was in possession of Bavaria and had at various times been recognized as ruler of most of those parts of the empire now included in Germany. The youngest son, Charles the Bald, had all the western portion of the Frankish possessions, while Lothaire, the eldest, had been designated as emperor and ruled over Italy and the district lying between the possessions of the younger brothers. Charles and Louis promptly combined to resist the attempts of Lothaire to assert his superiority as emperor, and defeated him at Fontenay (841). The treaty of Verdun, which followed, is one of the most memorable in the history of western Europe.[52] [Illustration: Map of Treaty of Verdun] [Sidenote: Treaty of Verdun, 843.] In the negotiations which led up to the treaty of Verdun there appears to have been entire agreement among the three parties that Italy should go to Lothaire, Aquitaine to Charles the Bald, and Bavaria to Louis the German. The real difficulty lay in the disposal of the rest of the empire. It seemed appropriate that the older brother, as emperor, should have, in addition to Italy, the center of the Frankish dominions, including the capital, Aix-la-Chapelle. A state of the most artificial kind, extending from Rome to northern Holland, was thus created, which had no natural unity of language or custom. Louis the German was assigned, in addition to Bavaria, the country north of Lombardy and westward to the Rhine. As for Charles the Bald, his realm included a great part of what is France to-day, as well as the Spanish March and Flanders.