Chi Rho - Christian Accounts of Constantine's Adoption of The Chi-Rho

Christian Accounts of Constantine's Adoption of The Chi-Rho

According to Lactantius, a Latin historian of North African origins saved from poverty by the patronage of Emperor Constantine I (r. 306–337) as tutor to his son Crispus, Constantine had dreamt of being ordered to put a "heavenly divine symbol" (Latin: coeleste signum dei) on the shields of his soldiers. The description of the actual symbol chosen by Emperor Constantine the next morning, as reported by Lactantius, is not very clear: it closely resembles a Chi-Rho or a staurogram, a similar Christian symbol. That very day Constantine's army fought the forces of Maxentius and won the Battle of the Milvian Bridge (312), outside Rome.

Writing in Greek, Eusebius of Caesarea (died in 339), the bishop who wrote the first surviving general history of the early Christian churches, gave two different accounts of the events. In his church history, written shortly after the battle, when Eusebius didn't yet have any contact with Constantine, he doesn't mention any dream or vision, but compares the defeat of Maxentius (drowned in the Tiber) to that of the biblical pharaoh and credits Constantine's victory to divine protection.

In a memoir of the Roman emperor that Eusebius wrote after Constantine's death (On the Life of Constantine, circa 337–339), a miraculous appearance came in Gaul long before the Battle of the Milvian Bridge. In this later version, the Roman emperor had been pondering the misfortunes that befall commanders that invoke the help of many different gods, and decided to seek divine aid in the forthcoming battle from the One God. At noon, Constantine saw a cross of light imposed over the sun. Attached to it, in Greek characters, was the saying "Τούτῳ Νίκα!". Not only Constantine, but the whole army saw the miracle. That night, Christ appeared to the Roman emperor in a dream and told him to make a replica of the sign he had seen in the sky, which would be a sure defence in battle.

Eusebius wrote in the Vita that Constantine himself had told him this story "and confirmed it with oaths" late in life "when I was deemed worthy of his acquaintance and company." "Indeed", says Eusebius, "had anyone else told this story, it would not have been easy to accept it."

Eusebius also left a description of the labarum, the military standard which incorporated the Chi-Rho sign, used by Emperor Constantine in his later wars against Licinius.