near Verona, Italy — 312
A pagan Emperor sees a cross in the sky
Emperor Constantine and others see a luminous cross in the sky. The emperor establishes Christianity in Rome. Fig. 46: The vision of Emperor Constantine Note that luminous crosses in the sky are not very unusual. They are caused by refraction phenomena similar to what one may observe by looking at a bright light through the mesh of a screen door. In this particular case the emperor is said to have seen luminous writing that read “In hoc signo vinces” (You will win through this Sign), which would eliminate the optical phenomenon as a simple explanation. However the writing may have been seen (or even heard) in a vision rather than an actual observation in the sky. In his remarkable book, L ‘Atmosphere et les Grands Phenomenes de la Nature (Paris: Hachette 1905), Camille Flammarion gives many examples of similar phenomena caused by reflexions or refraction due to ice crystals or water droplets in the atmosphere. Whether the cross was a natural phenomenon or not, this case is so important that it deserves special comments. There are two main sources for the story. One comes from Eusebius, the other from Lactantius. They do not provide an exact location, and contain contradictions. (The later sources are historically not very valuable.) Fig. 47: Cross-shaped atmospheric illusions Eusebius described the same events in the life of Constantine in two separate books. In the earliest of these he does not refer to the cross in the sky, literally as if it had never happened. In the later book he tells that before Constantine marched to Rome to battle Maxentius, he and all his soldiers witnessed a cross in the sky. That night, when asleep, the emperor had a dream in which Christ instructed him to make a copy of the sign they had seen, for use in all future battles. Lactantius, on the other hand, did not mention the cross in the sky at all. Instead he wrote that Constantine, while in the vicinity of Rome and before the battle with Maxentius, was simply instructed in a dream to use a special symbol, not forever but in the battle at hand. Eusebius wrote that the symbol consisted of a cross with the Christ monogram (the chi-roh) at the top. Lactantius wrote that the symbol was itself the chi-roh. Constantine had already experienced a vision in 310 AD, as the appearance of the pagan god, Apollo, whom the emperor worshipped as a sun god. It is odd that he should have met gods from two opposing religions in the space of two years. The inference is that Constantine’s only real vision was in 310 AD, and that he or someone else recycled it for the conversion story of 312 AD. Constantine had already used the sign of the cross (even the Latin cross) on his coins before his conversion, in reference to the Sun.
Source: Case: W469