Ad Nationes by Tertullian
Chapter XI. --The Absurd Cavil of the Ass's Head Disposed of.
In this matter we are (said to be) guilty not merely of forsaking the religion of the community, but of introducing a monstrous superstition; for some among you have dreamed that our god is an ass's head, -- an absurdity which Cornelius Tacitus first suggested. In the fourth book of his histories, where he is treating of the Jewish war, he begins his description with the origin of that nation, and gives his own views respecting both the origin and the name of their religion. He relates that the Jews, in their migration in the desert, when suffering for want of water, escaped by following for guides some wild asses, which they supposed to be going in quest of water after pasture, and that on this account the image of one of these animals was worshipped by the Jews. From this, I suppose, it was presumed that we, too, from our close connection with the Jewish religion, have ours consecrated under the same emblematic form. The same Cornelius Tacitus, however, -- who, to say the truth, is most loquacious in falsehood -- forgetting his later statement, relates how Pompey the Great, after conquering the Jews and capturing Jerusalem, entered the temple, but found nothing in the shape of an image, though he examined the place carefully. Where, then, should their God have been found? Nowhere else, of course, than in so memorable a temple which was carefully shut to all but the priests, and into which there could be no fear of a stranger entering. But what apology must I here offer for what I am going to say, when I have no other object at the moment than to make a passing remark or two in a general way which shall be equally applicable to yourselves? Suppose that our God, then, be an asinine person, will you at all events deny that you possess the same characteristics with ourselves in that matter? (Not their heads only, but) entire asses, are, to be sure, objects of adoration to you, along with their tutelar Epona; and all herds, and cattle, and beasts you consecrate, and their stables into the bargain! This, perhaps, is your grievance against us, that, when surrounded by cattle-worshippers of every kind we are simply devoted to asses!