Justice at last overtook Thassilo. He was summoned to appear before the Parliament at Ingelheim. The defeat of the Avars had so completely demoralized him that he did not dare to disobey the summons. He failed to clear himself from the charge of treason. His own followers testified against him. The indictment against him which called for the severest penalty was based upon this article in the Frankish statutes: “Whoever shall fail to keep faith with the kingdom, whoever shall break his vows to the King, whoever shall ally himself with the enemies of the kingdom, shall forfeit his life.” The death penalty was unanimously pronounced. Charlemagne asked him what he would do if his life were spared; whereupon Thassilo, as a proof of his repentance, agreed to spend the rest of his days in a monastery, received the tonsure at St. Goar, and was sent from there to Fulda.[38] Charlemagne declared his ducal title extinguished, assigned Frankish counts to the districts of Bavaria, and incorporated it in the Frankish kingdom. The year 790 was one long remembered by the Franks, for it was the only peaceable year in Charlemagne’s long reign. Preparations, however, had to be made to punish the Avars and prevent raids in future. The Avars, living between the Enns[39] and the Sau,[40] were of Hunnish stock, for which reason they are sometimes called Huns in the old chronicle. They inherited not only the pillaging habits of their ancestors, who swept over Germany like a deluge in the fifth century, but the almost countless treasures, or a considerable part of the treasure, which their fathers had stolen. The defences which they built on their frontiers were of a peculiar kind. They were called “rings”; each one of them was sufficiently large to enclose a number of villages, and consisted of strong walls, ten feet high and as many wide, constructed of tree-trunks and rocks cemented together and surmounted by densely planted thorn bushes. Behind such walls, the Avars thought they were secure against any enemy; but they were soon to learn their mistake.