Melanchthon and Luther diverged in their use of this picture from the older and more harmless interpretation, i.e. that which saw in it a reference to earthly trials, or a judgment on the politics of the Pope. They, on the contrary, regarded it as a denunciation by heaven of the Papacy itself and of the Roman Church with all its “abominations.” Quite possibly the transition had been quietly effected by the Bohemian Brethren. Luther, however, says Lange, “was the first to make it public property.” “The Pope-Ass is for this reason the most interesting example of the whole teratological literature, because in it we can see the transition visibly effected.” The same author detects in the joint work of the two Wittenbergers “a polemical tone hitherto unheard of”; of Melanchthon’s Pope-Ass, he says: “It is probably the most unworthy work we have of Melanchthon’s. He himself naturally believed implicitly in what he wrote.... That Melanchthon acquitted himself of his task with particular skill cannot be affirmed.”[430] Just as the Monk-Calf had been applied to Luther himself previous to his own polemical interpretation of it, so, after the appearance of his and Melanchthon’s joint publication, both the Calf and the Ass were repeatedly taken by the Catholic controversialists to represent Luther and his innovations. The sixteenth century, as already hinted, loved to dwell upon and expound such freaks of nature. Authors of repute had done so before Luther, at least to the extent of making such the subject of indifferent compositions, as the poet J. Franciscus Vitalis of Palermo had done (“_De monstro nato_”) in the case of a monstrosity said to have been born at Ravenna in 1511 or 1512; the Humanist Jacob Locher, at the turn of the fifteenth and sixteenth centuries, dealt with a similar case in his “_Carmen heroicum_.” Conrad Lycosthenes published at Basle, in 1557, a compendium of the prodigies of nature (“_Prodigiorum ac ostentorum chronicon_”), in which he instances a large number of such freaks famous even before Luther’s day. Of the earlier Humanists Sebastian Brant composed some Elegies on the Marvels of Nature. The Wittenberg work on the Calf and Ass must be put in its proper setting, and judged according to the standard of its age; although, owing to its religious bias, it far exceeds in extravagance anything that had appeared so far, it nevertheless was an outgrowth of its time. 3. Proofs of the Divine Mission. Miracles and Prophecies How was Luther to give actual proof of the reality of his call and of his mission to introduce such far-reaching ecclesiastical innovations?