Nearly contemporary with this was the celebrated case of Otho, Duke of Bavaria, perhaps the most noteworthy example of a judicial appeal to the sword. A worthless adventurer, named Egeno, accused Otho of conspiring against the life of Henry IV. In a diet held at Mainz, the duke was commanded to disprove the charge by doing battle with his accuser within six weeks. According to some authorities, his pride revolted at meeting an adversary so far his inferior; according to others, he was prevented from appearing in the lists only by the refusal of the emperor to grant him a safe conduct. Be this as it may, the appointed term elapsed, his default of appearance caused judgment to be taken against him, and his duchy was accordingly confiscated. It was bestowed on Welf, son of Azo d’Este and of Cunigunda, descendant and heiress of the ancient Guelfic Agilolfings; and thus, on the basis of a judicial duel, was founded the second Bavarian house of Guelf, from which have sprung so many royal and noble lines, including their Guelfic Majesties of Britain. Some years later, the emperor himself offered to disprove by the same means a similar accusation brought against him by a certain Reginger, of endeavoring to assassinate his rival, Rodolph of Suabia. Ulric of Cosheim, however, who was involved in the accusation, insisted on taking his place, and a day was appointed for the combat, which was prevented only by the opportune death of Reginger.[370] Scarcely less impressive in its results, and even more remarkable in itself, as exhibiting the duel invested with legislative as well as judicial functions, is the case wherein the wager of battle was employed in 1180 to break the overgrown power of Henry the Lion. That puissant Duke of Saxony and Bavaria had long divided the power of the empire and defied the repeated efforts of Frederic Barbarossa to punish his constantly recurring rebellions. Cited to appear and answer for his treasons in successive diets, he constantly refused, on the plea that the law required him to have a trial within his own dominions. At length, in the diet of Würzburg, a noble arose and declared himself ready to prove by the single combat that the emperor could legally cite his princes before him at any place that he might select within the limits of the empire. Of course there was none to take up the challenge, and Frederic was enabled to erect the principle thus asserted into a binding law. Henry was condemned by default, and his confiscated possessions were shared between those who had arranged and enacted the comedy.[371]