Labarum Cross

Vision of Constantine

On the evening of October 27, 312, with his army preparing for the Battle of the Milvian Bridge, the emperor Constantine Iclaimed to have had a vision which led him to fight under the protection of the Christian God.

Lactantius states^[8] that, in the night before the battle, Constantine was commanded in a dream to "delineate the heavenly sign on the shields of his soldiers". He obeyed and marked the shields with a sign "denoting Christ". Lactantius describes that sign as a "staurogram", or a Latin cross with its upper end rounded in a P-like fashion, rather than the better knownChi-Rho sign described by Eusebius of Caesarea. Thus, it had both the form of a cross and the monogram of Christ's name from the formed letters "X" and "P", the first letters of Christ's name in Greek.

From Eusebius, two accounts of a battle survive. The first, shorter one in the Ecclesiastical History leaves no doubt that God helped Constantine but doesn't mention any vision. In his later Life of Constantine, Eusebius gives a detailed account of a vision and stresses that he had heard the story from the emperor himself. According to this version, Constantine with his army was marching somewhere (Eusebius doesn't specify the actual location of the event, but it clearly isn't in the camp at Rome) when he looked up to the sun and saw a cross of light above it, and with it the Greek words Ἐν Τούτῳ Νίκα. The traditionally employed Latin translation of the Greek is in hoc signo vinces— literally "In this sign, you will conquer." However, a direct translation from the original Greek text of Eusebius into English gives the phrase "By this, conquer!"^[9]

At first he was unsure of the meaning of the apparition, but the following night he had a dream in which Christ explained to him that he should use the sign against his enemies. Eusebius then continues to describe the labarum, the military standard used by Constantine in his later wars against Licinius, showing the Chi-Rho sign.^[10]

Those two accounts can hardly be reconciled with each other, though they have been merged in popular notion into Constantine seeing the Chi-Rho sign on the evening before the battle. Both authors agree that the sign was not readily understandable as denoting Christ, which corresponds with the fact that there is no certain evidence of the use of the letters chi and rho as a Christian sign before Constantine. Its first appearance is on a Constantinian silver coin from c. 317, which proves that Constantine did use the sign at that time, though not very prominently.^[11] He made extensive use of the Chi-Rho and the labarum only later in the conflict with Licinius.

The vision has been interpreted in a solar context (e.g. as a solar halo phenomenon), which would have been reshaped to fit with the Christian beliefs of the later Constantine.

An alternate explanation of the intersecting celestial symbol has been advanced by George Latura, which claims that Plato's visible god in Timaeus is in fact the intersection of the Milky Way and the Zodiacal Light, a rare apparition important to pagan beliefs that Christian bishops reinvented as a Christian symbol.^[12]