which they had heretofore been subject. Louis, having attempted in
vain to negotiate with the rebels, made up his mind to act, and
summoned the host of Francia, Burgundy, and even of Saxony and
Alemannia, to gather at Vannes in August 818. The Frankish troops
pushed their way into the enemy's territory without having to fight a
regular battle, as the Bretons, following their customary tactics, preferred
to disappear from sight and merely harass their cuciny. The latter
could do no more thau ravage the country, but Morvan was killed in a
skirmish. His countrymen then abandoned the struggle, and at the
end of a month the Emperor re-entered Angers, having exacted promises
of submission from the more powerful of the Breton chiefs. Their submission, however, did not last long. In 822, a certain Wihomarch
repeated Morvan's attempt. The expeditions led against him by the
Frankish counts of the march of Brittany or by the Emperor himself were
marked only by the wasting of the country, and produced no permanent
results. Not until 826 did a new system ensure a measure of tranquillity.
Louis then recognised the authority over the Bretons of a chief of their
own race, Nomenoë, to whom he gave the title of missus and who in
return did homage to him and took the oath of fealty. But the union
of Brittany under a single head was a dangerous measure.
Louis was
blind to its disadvantages, but they were destined to have disastrous
results in the reign of his successor.
Events within the realm were to begin the disorganisation of Louis's government and ultimately bring about the disruption of the empire founded by Charlemagne. In July 817 at the assembly of Aix-la-Chapelle, the Emperor had decided to take measures to establish the succession, or rather to cause the arrangements already made by himself and a few of his confidential advisers to be ratified by the lay and ecclesiastical magnates jointly. The Frankish principle by which the dominions of a deceased sovereign were divided among his sons, was still too living a thing (it lasted, indeed, as long as the Carolingian dynasty itself) to allow of the exclusion of any one of Louis's sons from the succession. The principle had already been applied in 806, and Louis had in some sort recognised it afresh by entrusting two of his sons with the government of two of his kingdoms, while at the same time leaving a third in the hands of Bernard of Italy. But on the other hand, the Emperor and his chief advisers were no less firmly attached to the principle of the unity of the Empire, "by ignoring which we should introduce confusion into the Church, and offend Him in Whose Hands are the rights of all kingdoins." "Would God, the Almighty," wrote one of the most illustrious of the thinkers upholding the system of the unity of the Empire, Archbishop Agobard of Lyons, "that all men, united under a single king, were governed by a single law! This would be the best method of maintaining peace in the City of God and equity among the nations." And the wisest and most influential of the clergy in
