The Chi Rho with a wreath symbolizing the victory of the Resurrection, above Roman soldiers, ca. 350.
The Chi Rho is one of the earliest forms of christogram, and is used by Christians. It is formed by superimposing the first two letters in the Greek spelling of the word Christ ( Greek : "Χριστός" ), chi = ch and rho = r, in such a way to produce the monogram ☧. Although not technically a cross, the Chi Rho invokes the crucifixion of Jesus as well as symbolizing his status as the Christ.
The Chi-Rho symbol was also used by pagan Greek scribes to mark, in the margin, a particularly valuable or relevant passage; the combined letters Chi and Rho standing for chrēston, meaning "good."Some coins of Ptolemy III Euergetes were marked with a 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 Constantine I 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 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.
Constantine's labarum, a standard incorporating the wreathed Chi-Rho, from an antique silver medal.In a memoir of the emperor that Eusebius wrote after Constantine's death (On the Life of Constantine, ca 337‑339), a miraculous appearance came in Gaul long before the Milvian Bridge battle. In this later version, the 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 "Τούτω Νίκα!" [6]. Not only Constantine, but the whole army saw the miracle. That night Christ appeared to the 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 defense 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 Constantine in his later wars against Licinius.
The use of a wreath around the Chi Rho symbolizes the victory of the Resurrection over death, and is an early visual representations of the connection between the Crucifixion of Jesus and his triumphal resurrection, as seen in the fourth century sarcophagus of Domitilla in Rome. Here, in the wreathed Chi Rho the death and resurrection of Christ are shown as inseparable, and the Resurrection is not merely a happy ending tucked at the end of the life of Christ on earth. Given the use of similar symbols on the Roman standard, this depiction also conveyed another victory, namely that of the Christian faith: the Roman soldiers who had once arrested Jesus and marched him to Calvary now walked under the banner of a resurrected Christ.
After Constantine the Chi-Rho became part of the official imperial insignia. Archaeologists have uncovered evidence demonstrating that the Chi Rho was emblazoned on the helmets of some Late Roman soldiers. Coins and medallions minted during Constantine's reign also bore the Chi Rho. By the year 350, the Chi Rho began to be used on Christian sarcophagi and frescoes. [A.E.M.] The usurper Magnentius appears to have been the first to use the Chi-Rho monogram flanked by Alpha and Omega, on the reverse of some coins minted in 353. In Roman Britannia, a tesselated mosaic pavement was uncovered at Hinton St Mary, Dorset, in 1963:. On stylistic grounds it is dated to the fourth century; its central roundel represents a beardless male head and bust draped in a pallium in front of the Chi-Rho symbol, flanked by pomegranates, symbols of eternal life. Another Romano-British Chi-Rho, in fresco, was found at the site of a villa at Lullingstone (illustrated). The symbol was also found on Late Roman Christian signet rings in Britain
