After his return from Italy Charles held his court at Worms and summoned Tassilo before him as the first step in acknowledging the overlordship of the Frankish monarch. In the eyes of Charles, swift dealing with a disobedient vassal was all the more necessary, because Tassilo, by his marriage with the daughter of Desiderius, might easily make himself the center of a revival of pro-Lombard feeling in Italy. Three Frankish armies from different quarters invaded Bavaria, and Tassilo soon found himself forced by this display of superior strength to give up his dreams of independent power. He formally resigned his duchy and received it back again from Charles’ hands, at the same time taking an oath as vassal and giving hostages, among whom was his own son. But not long after this Tassilo, who complained openly that his position of dependence was insupportable, was charged by members of his people with intriguing with the Avars. He was accused of treachery, and was condemned to death by legal process. But the sentence was reduced by Charles’ intervention to imprisonment in a monastery. His wife and children met a like fate, and from this time on Bavaria was treated as Frankish territory. Like Saxony, it was divided into jurisdictions under counts and placed under the supreme military control of one superior official. The overthrow of Bavaria as a separate power laid the foundation of a consolidated Germany, North and South, and, as in Middle Germany, there was the same system of counties and bishoprics. Unity was still far from being thoroughly realized, but that the germ of national consciousness was already present is proved by the readiness of the Bavarians, after the loss of their ruling duke and their autonomy, to coöperate with the Franks in resisting the attacks of the Avars. Just at the time that the tension in Bavaria was reaching its acute stage, the situation in the Lombard Duchy of Benevento, whose Duke Arichis seemed to be taking his cue from Tassilo, demanded attention. There were no actual hostilities, for the presence of Charles in the duchy was enough to bring the turbulent Duke to reason. His position of vassalage was marked by a payment of an annual tribute of 7000 solidi. The duchy was mildly treated by Charles because it was useful as a buffer against the provinces of the Eastern Empire, with which his relations were far from being always friendly. The result was that the Beneventines played a double rôle, sometimes befriending the Greeks and rejecting the Frank overlordship, and on other occasions engaging in hostilities with their Southern neighbors, as allies of the Franks. There were a number of Frankish expeditions necessary to keep the Lombards of Benevento and their dukes in mind of their duty as a vassal state, and once there was a noteworthy failure of Frankish arms in 792, when the campaign they had begun in the territory of the duchy was abandoned.