Saxons and Scandinavians came into contact with one another. The monastery of Corvey or New Corbie (822) and the bishopric of Ham- burg (831) were founded to safeguard Christianity in the country thus evangelised. When in 826 the Danish prince Harold came to be baptised at Mayence with several hundreds of his followers, the ceremony was made the opportunity for splendid entertainments at which the whole court was present, and was looked upon by the circle surrounding the Emperor as a triumph. But attacks by way of the sea were already beginning against the Frankish Empire. In 820 a band of pirates had attempted to land, first in Frisia, and then on the shores of the lower Seine, but being beaten off by the inhabitants they had been forced to content themselves with retiring to pillage the island of Bouin off the coast of La Vendée. In 829 a Scandinavian invasion of Saxony had momentarily alarmed Louis, but had led to nothing. In short, it may be said that for the first part of the reign Louis's dominions had been exempt from the ravages of the Vikings, but the tempest which was to rage so furiously a few years later was already seen to be gathering.
The Slavonic populations which bordered Frankish Germany on the east were also kept within due bounds. In 816 the heorbann of the Saxons and East Franks, called out against the rebellious Sorbs, compelled them to renew their oaths of submission. Next year the Frankish counts in charge of the frontier successfully beat off an attack by Slavomir, the prince of the Obotrites, who, being made prisoner a little later and accused before the Emperor by his own subjects, was deposed, his place being given to his rival Ceadrag (818). The new prince, however, before long deserted his former allies, joined forces with the Danes, and unsuccessfully renewed the struggle with the Franks. The latter found a more formidable opponent in the person of Liudevit, a prince who had succeeded in reducing to his obedience part of the population of Pannonia and was menacing the Frankish frontier between the Drave and the Save. An expedition sent against him under the Marquess of Friuli, Cadolah, was not successful. Cadolah died during the campaign, and the Slovenes invaded the imperial territory: (820). It was only through an alliance with one of Liudevit's foes, Bozna, the Grand Župan of the Croats, that the Franks in their turn were enabled to spread destruction through the enemy's country, and to force the tribes of Carniola and Carinthia, who had thrown off their allegiance, to submit afresh. Liudevit himself made his submission next year, and peace was maintained upon the eastern frontier till 827-8, when an irruption of the Bulgarians into Pannonia necessitated another Frankish expedition, headed this time by the Emperor's son Louis the German. By way of compensation, unbroken peace reigned or the extreme southern frontier of the dominions of Louis. The Lombard populations of the south of Italy continued to be practically independent of Frankish rule. Louis made no attempt to exert any effective
