The last-named kingdom, the most considerable of the three, remained under the direct government of Louis the Debonnair, and at the same time of his son Lothaire, sharing the title of emperor.

The two other sons, Pepin and Louis, entered, notwithstanding their childhood, upon immediate possession, the one of Aquitaine and the other of Bavaria, under the superior authority of their father and their brother, the joint emperors.
Charlemagne had vigorously maintained the unity of the empire, for all that he had delegated to two of his sons, Pepin and Louis, the government of Italy and Aquitaine, with the title of king.

Louis the Debonnair, whilst regulating beforehand the division of his dominion, likewise desired, as he said, to maintain the unity of the empire.

But he forgot that he was no Charlemagne.
It was not long before numerous mournful experiences showed to what extent the unity of the empire required personal superiority in the emperor, and how rapid would be the decay of the fabric when there remained nothing but the title of the founder.
In 816 Pope Stephen IV.

came to France to consecrate Louis the Debonnair emperor.