Nicene and Post-Nicene Fathers, Vol. II:
City of God: Chapter 6

Chapter 6.—That the Gods Exacted No Penalty for the Fratricidal Act of Romulus.

I add another instance:  If the sins of men so greatly incensed those divinities, that they abandoned Troy to fire and sword to punish the crime of Paris, the murder of Romulus’ brother ought to have incensed them more against the Romans than the cajoling of a Greek husband moved them against the Trojans:  fratricide in a newly-born city should have provoked them more than adultery in a city already flourishing.  It makes no difference to the question we now discuss, whether Romulus ordered his brother to be slain, or slew him with his own hand; it is a crime which many shamelessly deny, many through shame doubt, many in grief disguise.  And we shall not pause to examine and weigh the testimonies of historical writers on the subject.  All agree that the brother of Romulus was slain, not by enemies, not by strangers.  If it was Romulus who either commanded or perpetrated this crime; Romulus was more truly the head of the Romans than Paris of the Trojans; why then did he who carried off another man’s wife bring down the anger of the gods on the Trojans, while he who took his brother’s life obtained the guardianship of those same gods?  If, on the other hand, that crime was not wrought either by the hand or will of Romulus, then the whole city is chargeable with it, because it did not see to its punishment, and thus committed, not fratricide, but parricide, which is worse.  For both brothers were the founders of that city, of which the one was by villainy prevented from being a ruler.  So far as I see, then, no evil can be ascribed to Troy which warranted the gods in abandoning it to destruction, nor any good to Rome which accounts for the gods visiting it with prosperity; unless the truth be, that they fled from Troy because they were vanquished, and betook themselves to Rome to practise their characteristic deceptions there.  Nevertheless they kept a footing for themselves in Troy, that they might deceive future inhabitants who re-peopled these lands; while at Rome, by a wider exercise of their malignant arts, they exulted in more abundant honors.