Agobard of Lyons, "On Hail and Thunder" (9th Century)
A certain stupidity was spread a few years ago, when some cattle died, so that people said that Grimaldus, the Duke of Benevento, had sent men with powder that they sprinkled through the fields and mountains, meadows and springs – because he was hostile to the most Christian Emperor Charles, and cattle died from this sprinkled powder. We have heard of, and seen, many men seized for this reason, some of them struck down and slain, but most of them tied to boards, thrown into the river, and killed. And, what is truly amazing, the very ones who were seized would give evidence against themselves, saying that they had such a powder and they had sprinkled it. For thus the devil, when his power was received into them by the secret and righteous justice of God, was able to enter them to such an extent that they became false witnesses against themselves to the point of death. And neither instruction nor torture nor death itself deterred them from daring to speak this falsehood against themselves.
This was believed by everyone, so that there was scarcely anyone to whom it seemed absurd. They did not consider rationally, how such a powder that would kill only the cattle and not the rest of the animals could have been made, or how such stuff could have been carried across regions so broad that people could not have sprinkled them with powder, not even if all the Beneventan men and women, old and young, had come through the region with three full carts of powder.
So much stupidity has already oppressed the wretched world that Christians now believe things so absurd that no one ever before could persuade the pagans to believe them, even though these pagans were ignorant of the Creator of all things. On this account, therefore, we have brought this last incident into the midst to our discourse, because it is similar to the topic on which we are speaking and can give an example of inane seduction and true impoverishment of sense.