Archbishop of Mainz, according to tradition, was devoured by mice. The story says that in 970 there was a great famine in Germany, and Hatto, that there might be better store for the rich, assembled the poor in a barn, and burnt them to death, saying, “They are like mice, only good to devour the corn.” By and by an army of mice came against the arch bishop, and the abbot, to escape the plague, removed to a tower on the Rhine, but hither came the mouse-army by hundreds and thousands, and ate the bishop up. The tower is still called Mouse-tower. Southey has a ballad on the subject, but makes the invaders an army of rats. (See Mouse Tower; Pied Piper.)
And in at the windows, and in at the door, And through the walls by thousands they pour, And down through the ceiling, and up through the floor, From the right and the left, from behind and before, From within and without, from above and below And all at once to the bishop they go. They have wetted their teeth against the stones, And now they are picking the bishop's bones; They gnawed the flesh from every limb, For they were sent to do judgment on him.
A very similar legend is told of Count Graaf, a wicked and powerful chief, who raised a tower in the midst of the Rhine for the purpose of exacting tolls. If any boat or barge attempted to evade the exaction, the warders of the tower shot the crew with cross-bows. Amongst other ways of making himself rich was buying up corn. One year a sad famine prevailed, and the count made a harvest of the distress; but an army of rats, pressed by hunger, invaded his tower, and falling on the old baron, worried him to death, and then devoured him. (Legends of the Rhine.)
Widerolf, bishop of Strasburg (in 997), was devoured by mice in the seventeenth year of his episcopate, because he suppressed the convent of Seltzen, on the Rhine.
Bishop Adolf of Cologne was devoured by mice or rats in 1112. Frei herr von Güttengen collected the poor in a great barn, and barnt them to death; and being invaded by rats and mice, ran to his castle of Güttingen. The vermin, however, pursued him and ate him clean to the bones, after which his castle sank to the bottom of the lake, “where it may still be seen.”
A similar tale is recorded in the chronicles of William of Mulsburg, book ii. p. 313 (Bone's edition). Mice or rats. Giraldus Cambrensis says. The larger sort of mice are called rats. (Itinerary, book xi. 2.) On the other hand, many rats are called mice, as mustela Alpina, the mus Indicus, the mus aquaticus, the mus Pharaonis, etc.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894