TASSILO II, Duke of BAVARIA. – Son of Chiltrude, sister of Pippin the Short, he succeeded his father Odilo with the intervention of his uncle (748); d. c. 13 Dec. 798.
Although he had sworn fidelity at Compiègne (757), Tassilo, however, did not abandon the thought of becoming independent. During the Aquitanian campaign, he suddenly left the Frankish army (763) to return to Bavaria. His reconciliation with Pippin took place in 765 through the mediation of the Pope; but it was not sincere. Charlemagne, distrusting this vassal, required him to take an oath at Worms (781) and to deliver twelve hostages. Tassilo revealed himself in 786, when his wife Liutberga, daughter of Desiderius, the last King of the Lombards, incited him to betray the Emperor and avenge the defeat of Arechis, Duke of Benevento, her brother. Tassilo made an agreement with the Avars and urged them to fight the Franks; but Charlemagne summoned him to appear at Worms to answer for the crime of high treason (787). The Duke refused to obey, but the invasion of his territories by the Frankish army forced him to submit, and at Ingelheim (788) he was condemned to death as a traitor. The sentence, however, was commuted to relegation in a monastery, perhaps that of St Goar near Koblenz. In 794 he solemnly renounced all his rights to the Duchy of Bavaria, both in his own name and on behalf of his sons—who, moreover, were already confined in a monastery (cf. *Capitularia regum Francorum*, in *MGH*, ed. A. Boretius-V. Krause, I, Hannover 1883, p. 74, n. 28, art. 3). It is uncertain whether, after this, Tassilo retired to the abbey of Jumièges in Normandy. The chalice offered by Tassilo to Kremsmünster is reproduced under V. CALICE.