It was only when the great voyages of discovery substituted ascertained fact for theological reasoning in this province that its authority was broken.
The same sort of science flourished in the Bestiaries, which were used everywhere, and especially in the pulpits, for the edification of the faithful.

In all of these, as in that compiled early in the thirteenth century by an ecclesiastic, William of Normandy, we have this lesson, borrowed from the Physiologus: "The lioness giveth birth to cubs which remain three days without life.

Then cometh the lion, breatheth upon them, and bringeth them to life....

Thus it is that Jesus Christ during three days was deprived of life, but God the Father raised him gloriously." Pious use was constantly made of this science, especially by monkish preachers.

The phoenix rising from his ashes proves the doctrine of the resurrection; the structure and mischief of monkeys proves the existence of demons; the fact that certain monkeys have no tails proves that Satan has been shorn of his glory; the weasel, which "constantly changes its place, is a type of the man estranged from the word of God, who findeth no rest." The moral treatises of the time often took the form of works on natural history, in order the more fully to exploit these religious teachings of Nature.