Augustine, City of God, Book XXI: THAT IT IS POSSIBLE FOR A THING TO BECOME DIFFERENT FROM WHAT IT WAS FORMERLY KNOWN CHARACTARISTICALLY TO BE
From the book of Marcus Varro, entitled, Of the Race of the Roman People, I cite word for word the following instance: "There occurred a remarkable celestial portent; for Castor records that, in the brilliant star Venus, called Vesperugo by Plautus, and the lovely Hesperus by Homer, there occurred so strange a prodigy, that it changed its color, size, form, course, which never happened before nor since. Adrastus of Cyzicus, and Dion of Naples, famous mathematicians, said that this occurred in the reign of Ogyges." So great an author as Varro would certainly not have called this a portent had it not seemed to be contrary to nature. For we say that all portents are contrary to nature; but they are not so. For how is that contrary to nature which happens by the will of God, since the will of so mighty a Creator is certainly the nature of each created thing? A portent, therefore, happens not contrary to nature, but contrary to what we know as nature. But who can number the multitude of portents recorded in profane histories? Let us then at present fix our attention on this one only which concerns the matter in hand. What is there so arranged by the Author of nature of heaven and earth as the exactly ordered course of the stars? What is there established by laws so sure and inflexible? And yet, when it pleased Him who with sovereignty and supreme power regulates all He has created, a star conspicuous among the rest by its size and splendor changed its color, size, form, and, most wonderful of all, the order and law of its course! Certainly that phenomenon disturbed the canons of the astronomers, if there were any then, by which they tabulate, as by unerring computation, the past and future movements of the stars, so as to take upon them to affirm that this which happened to the morning star (Venus) never happened before nor since. ... But possibly, though Varro is a heathen historian, and a very learned one, they may disbelieve that what I have cited from him truly occurred; or they may say the example is invalid, because the star did not for any length of time continue to follow its new course, but returned to its ordinary orbit.