The years during which Pippin governed the Franks were marked in their regal annals by four obscure names. Theuderich, the weak king who had been drawn from the cloister to sit on his brother’s throne,[41] died in 691: he was followed by his two infant sons, Chlodovech III. (691-5), and Childebert III. (695-711), both of whom were recognised alike in Neustria and Austrasia, but had no real authority. Chlodovech died while yet a boy: Childebert survived to early manhood, begat a son, and then hastened to the grave. Apparently the vices of their ancestors had sapped the vital energy of the later Merovings; scarce one of them survived to reach the age of thirty, and each long minority made the kingly power more and more shadowy, and the authority of the great mayor more and more real. Childebert III. was followed by one more young boy, his son Dagobert III. (711-16), the last of the four puppet kings in whose names the great Pippin swayed the Frankish sceptre. Footnote 41: See page 259. Pippin lived to a great age, and had the misfortune to lose in his declining years his two legitimate sons, Grimoald and Drogo, whom he had destined to succeed him. The heirs then remaining to him were Theudoald, a young boy, the son of Grimoald, and Carl [Charles Martel], an illegitimate son whom he had by a concubine named Alphaida. The former was only eight years of age, the latter twenty-five, but the old man designated the boy Theudoald as his successor, hoping that he might be spared to see him grow up to manhood. [Sidenote: Death of Pippin, 715.] He died, however, within a few months, and a strange problem was put before the Franks, whether they would tolerate a child-mayor ruling in the name of a child-king. Pippin’s widow Plectrudis tried to seize the reins of government in behalf of her little grandson, and some of the Austrasians adhered to her cause. As a precautionary measure she cast her husband’s natural son Charles into prison, knowing that many men regarded him as the only possible heir to Pippin’s position, since the idea of a child-mayor was preposterous. Plectrudis’ endeavour to rule in the name of her grandson proved, as might have been expected, a complete failure. The counts and dukes of Neustria hastened to take the opportunity of shaking off the domination of the Austrasians. They mustered in arms, chose a certain Raginfred, one of themselves, as Neustrian Mayor of the Palace, and raised an army to invade Austrasia in the name of the young Dagobert III. They did not shrink from allying themselves with the enemies of the state, the Frisians and Saxons, who attacked Austrasia from the rear, while they themselves, advancing through the Ardennes, wasted all the lands between Meuse and Rhine with fire and sword. Plectrudis and her grandson shut themselves up within the walls of Köln.