We may pass over without discussion the question whether Venus could possibly have borne Aeneas as a result of her liaison with Anchises, or whether Mars could have begotten Romulus from his intimacy with Numitor’s daughter. A very similar question arises even in our own Scriptures as to whether the fallen angels committed fornication with the ‘daughters of men,’ which brought into being a race of giants, men of extraordinary size and strength, who increased and peopled the earth. Let us argue both cases as one. If the adulteries we read about concerning Aeneas’ mother and Romulus’ father be true, how can the gods take offense at the adulteries of men, since they take such things as a matter of course among themselves? Even if the tales are untrue, the gods should not become angered at the real adulteries of men, since they are pleased to have false ones attributed to themselves. Besides, if the misconduct of Mars is discredited for the sake of saving Venus, then no divine seduction can excuse the mother of Romulus.
Further, she was a priestess of Vesta, and for that reason the gods were bound to wreak greater vengeance upon the Romans for her sacrilege than upon the Trojans for the adultery of Paris. The ancient Romans buried alive any Vestal priestesses caught in adultery, although they never punished by death other women guilty of the same crime. Thus, they inflicted severer penalties on what they regarded as the desecration of the shrines of the gods than on the violation of the marriage bond among men.
Here is another instance. If the crimes of mortals angered the gods so much that, when offended by the act of Paris, they abandoned Troy to destruction by fire and sword, then the murder of Romulus’ brother should have incensed them against the Romans—and much more than the deception of a Greek husband did against the Trojans. Surely, fratricide in a newly founded state should have provoked them more than adultery in a state already established in power. Moreover, it is irrelevant whether Romulus ordered the murder, or committed it with his own hand—as many boldly deny, or doubt in shame, or dissemble in sorrow. I need not delay, therefore, in examining in detail testimonies of many writers already verified. One thing is certain: Romulus’ brother was slain neither by open enemies nor by strangers.
Whether Romulus himself committed the murder or merely ordered its commission, the fact is that he was more fully master of the Romans than Paris was of the Trojans. Why, then, did the seducer of another man’s wife kindle the wrath of the gods, while the murderer of his own brother begged for the Romans the protection of the gods? If that crime was not committed by Romulus directly or indirectly, it still cried aloud for vengeance, and, since the whole state treated it as a light matter, the whole state committed the crime. Thus, the state slew not merely a brother, but, even worse, a father. The one brother was as much the founder of the state as the other; when one was removed by the crime, the other was thereby barred from becoming ruler.
I do not think there is any way of telling for what guilt Troy deserved to be abandoned by the gods and come to ruin, or for what good Rome deserved to become their abode and be set on the road to prosperity. Perhaps it was because the gods fled in defeat and betook themselves to the people they were to dupe and mislead. Or, better, they remained on the site of Troy to deceive the new settlers, according to their custom, while here in Rome, having greater scope for lying tricks, they were given greater honors and glory.
Augustine of Hippo, The City of God, Books I–VII