In his later
Life of Constantine (AD 337), Eusebius gives a detailed account of a vision (claiming that he had heard the story from the then already-deceased Constantine himself). (Oh yeah, he again repeats the Exodus motif he used earlier for the battle here.)
He said that about noon, when the day was already beginning to decline, he saw with his own eyes the trophy of a cross of light in the heavens, above the sun, and bearing the inscription,
Conquer by this. At this sight he himself was struck with amazement, and his whole army also, which followed him on this expedition, and witnessed the miracle. He said, moreover, that he doubted within himself what the import of this apparition could be. And while he continued to ponder and reason on its meaning, night suddenly came on; then in his sleep the Christ of God appeared to him with the same sign which he had seen in the heavens, and commanded him to make a likeness of that sign which he had seen in the heavens, and to use it as a safeguard in all engagements with his enemies.
At dawn of day he arose, and communicated the marvel to his friends: and then, calling together the workers in gold and precious stones, he sat in the midst of them, and described to them the figure of the sign he had seen, bidding them represent it in gold and precious stones. And this representation I myself have had an opportunity of seeing.
In this version of the story, Constantine, while marching with his army, looks up to the noonday sun and sees, along with his army, “a cross of light” (it isn’t specified just what shape or form this cross was) with the words Εν Τούτῳ Νίκα
En toutō níka. He was unsure of the meaning of the apparition at first, but the following night he had a dream where Christ appeared and explained to him that he should use the sign against his enemies. He then has a military standard made, the
labarum, as a result of the dream.
In Tyrannius Rufinus’ translation of books 10 and 11 of Eusebius’
Church History, the story gets even more elaborate. He adds the story of Constantine’s vision and dream and the construction of the
labarum from
Life of Constantine, but he changes the details: for one, only Constantine saw the vision (which occurred somewhere during the early hours), and he saw it in a dream. “While sleeping he saw toward the east the symbol of a cross gleaming with a fiery glow in the sky.” Rufinus adds in angels who here declare
En toutō níka to Constantine. It was after seeing these angels that Constantine made the
labarum. (Rufinus adds that he even made a golden cross for himself to hold!) In fact, Rufinus more explicitly portrays Constantine as already being almost Christian: he was already “a supporter of the Christian religion and a worshipper of the true God” but he had not yet accepted “the symbol of the Lord’s suffering.”
Where it kinda gets complicated is, that aside from the two authors who knew Constantine - Lactantius and Eusebius - the other contemporary witness to the battle, the Arch of Constantine, isn’t very explicit. In the inscription in the arch, Constantine claimed to have received victory due to being “inspired by the divine” (
instinctu divinitatis). But it isn’t clear just to what the ‘divine’ refers to at this point, since up to 324, Constantine still mainly used the imagery of the then-popular solar deity Sol Invictus in his official documents (such as coins), after which he began to use more overtly Christian symbols lik the
chi-rho for his official propaganda.
Where it gets difficult is the fact that the
chi-rho symbol was not really specifically Christian: it was also a common abbreviation for the word χρηστός
chrestos ‘good’ / ‘useful’. (You might say there’s a potential pun involved here, since by this time the words
Christos and
chrēstos were beginning to be pronounced / would have been pronounced nearly the same in Greek.) In fact, it’s pretty much used for any other word that have the letters chi (X) and rho (P) in it. In fact, a few scholars argue that it isn’t entirely clear whether Lactantius was actually talking about the
chi-rho or another symbol, the so-called staurogram (aka
tau-rho).
