Macrobius[204] relates that the Emperor Trajan, to prove the oracle of Heliopolis in Phoenicia, sent him a well-sealed letter in which nothing was written; the oracle commanded that a blank letter should also be sent to the emperor. The priests of the oracle were much surprised at this, not knowing the reason of it. Another time the same emperor sent to consult this same oracle to know whether he should return safe from his expedition against the Parthians. The oracle commanded that they should send him some branches of a knotted vine, which was sacred in his temple. Neither the emperor nor any one else could guess what that meant; but his body, or rather his bones, having been brought to Rome after his death, which happened during his journey, it was supposed that the oracle had intended to predict his death, and designate his fleshless bones, which somewhat resemble the branches of a vine. It is easy to explain this quite otherwise. If he had returned victorious, the vine being the source of wine which rejoices the heart of man, and is agreeable to both gods and men, would have typified his victory--and if the expedition had proved fruitless, the wood of the vine, which is useless for any kind of work, and only good for burning as firewood, might in that case signify the inutility of this expedition. It is allowed that the artifice, malice, and inventions of the heathen priests had much to do with the oracles; but are we to infer from this that the demon had no part in the matter? We must allow that as by degrees the light of the Gospel was spread in the world, the reign of the demon, ignorance, corruption of morals, and crime, diminished. The priests who pretended to predict, by the inspiration of the evil spirit, things concealed from mortal knowledge, or who misled the people by their illusions and impostures, were obliged to confess that the Christians imposed silence on them, either by the empire they exercised over the devil, or else by discovering the malice and knavishness of the priests, which the people had not dared to sound, from a blind respect which they had for this mystery of iniquity.