The power delegated to the demons at certain appointed and well-adjusted seasons, that they may give expression to their hostility to the city of God by stirring up against it the men who are under their influence, and may not only receive sacrifice from those who willingly offer it, but may also extort it from the unwilling by violent persecution; -- this power is found to be not merely harmless, but even useful to the Church, completing as it does the number of martyrs, whom the city of God esteems as all the more illustrious and honored citizens, because they have striven even to blood against the sin of impiety. If the ordinary language of the Church allowed it, we might more elegantly call these men our heroes. For this name is said to be derived from Juno, who in Greek is called Hêrê, and hence, according to the Greek myths, one of her sons was called Heros. And these fables mystically signified that Juno was mistress of the air, which they suppose to be inhabited by the demons and the heroes, understanding by heroes the souls of the well-deserving dead. But for a quite opposite reason would we call our martyrs heroes, -- supposing, as I said, that the usage of ecclesiastical language would admit of it, -- not because they lived along with the demons in the air, but because they conquered these demons or powers of the air, and among them Juno herself, be she what she may, not unsuitably represented, as she commonly is by the poets, as hostile to virtue, and jealous of men of mark aspiring to the heavens. Virgil, however, unhappily gives way, and yields to her; for, though he represents her as saying, "I am conquered by Æneas," 
Helenus gives Æneas himself this religious advice:
"Pay vows to Juno: overbear
Her queenly soul with gift and prayer." 
In conformity with this opinion, Porphyry -- expressing, however, not so much his own views as other people's -- says that a good god or genius cannot come to a man unless the evil genius has been first of all propitiated, implying that the evil deities had greater power than the good; for, until they have been appeased and give place, the good can give no assistance; and if the evil deities oppose, the good can give no help; whereas the evil can do injury without the good being able to prevent them. This is not the way of the true and truly holy religion; not thus do our martyrs conquer Juno, that is to say, the powers of the air, who envy the virtues of the pious. Our heroes, if we could so call them, overcome Hêrê, not by suppliant gifts, but by divine virtues. As Scipio, who conquered Africa by his valor, is more suitably styled Africanus than if he had appeased his enemies by gifts, and so won their mercy.