Labarum

The Roman emperor Constantine I (ruled 306 - 337) created a new military standard to be carried before his army which displayed the first two Greek letters of word Christ - Chi (χ) and Rho, (ρ) which came to be known as the labarum (☧). Constantine himself, however, continued to hold the title of Pontifex Maximus, chief priest of the classical pagan Roman religion. Many take this to mean that he was not a Christian, though he had an interest in the politics of Christianity, which has led some scholars to the conclusion that the labarum was not intended as a Christian symbol.

The etymology of the word before Constantine's usage of it is unclear. According to Lactantius (On the Deaths of the Persecutors, chapter 44), Constantine had dreamed of this emblem and a voice saying "In this sign you shall win" (In hoc signo vinces). On waking he ordered his soldiers to put the emblem on their shields; that very day they fought the forces of Maxentius and won the Battle of the Milvian Bridge (312), outside Rome.

Mythology characteristically differs in the details, but in every case, the details are meaningful, never random. Writing in Greek, Eusebius of Caesarea (died 339), the bishop who wrote the first surviving general history of the early Christian churches, gave two additional versions of Constantine's famous vision:

• According to the bishop's Historia ecclesiae ("Church History"), the emperor saw the vision in Gaul on his way to Rome, long before the battle with Maxentius: the phrase as he gives it was "Εν τουτο νικα" — literally, "In this, win!".
• In a later hagiographic memoir of the emperor that Eusebius wrote after Constantine's death ("On the Life of Constantine," ca 337‑339), the miraculous appearance came when the rival armies met at the Milvian Bridge. In this later version, the emperor had been pondering the logical question of misfortunes that befall armies 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 was the saying In hoc signo vinces. Not only Constantine, but the whole army saw the miracle. Constantine's modern biographer, the historian Ramsey MacMullen, comments: "If the sky writing was witnessed by 40,000 men, the true miracle lies in their unbroken silence about it" (Constantine, 1969). 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. Thus the element of the public miracle reinforces the element of the private dream.

In medieval art, the labarum theme is conspicuous by its absence, appearing suddenly in the Renaissance and classical periods, where the phrase is frequently shown written out in the sky.

Eusebius may have felt that the dream mytheme on its own needed reinforcement. Of the miracle, he 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."

Among the many soldiers depicted on the Arch of Constantine, which was erected just three years after the battle, the labarum does not appear, nor is there any hint of the miraculous affirmation of divine protection that had been witnessed, Eusebius avers, by so many. A grand opportunity for just the kind of political propaganda that the Arch otherwise was expressly built to present, would have been unaccountably missed, if Eusebius' oath-confirmed account can be trusted. Its inscription does say that the emperor had saved the res publica INSTINCTU DIVINITATIS MENTIS MAGNITUDINE ("by greatness of mind and by instinct [or impulse] of divinity"). Which divinity is not identified, though Sol Invictus— the Invincible Sun (also identifiable in Apollo or Mithras)— is inscribed on Constantine's coinage at this moment.

In his Historia ecclesiae Eusebius further reports that, after his victorious entry into Rome, Constantine had a statue of himself erected, "holding the sign of the Savior [the cross] in his right hand." There are no other reports to confirm such a conspicuous monument.

It has since been interpreted by Christians all over the world as a symbol of Christianity. Because it is composed of the combined chi and rho it is sometimes referred to as the "monogram of Christ". Protestant Christians, especially Restorationists, reject its use due to what they believe to be pagan origins—specifically, as a symbol of the sun god—and lack of use by the earliest Christians: forms of it only start to appear in the 3rd century, mostly on sarcophagi.

The interpretation of its use as a specifically Christian symbol is, however, reinforced by the fact that Julian the Apostate removed it from his insignia, and that it was restored to use by his Christian successors.

The name of the Basque swastika lauburu may come from labarum.

In Unicode, the Chi-Rho symbol is U+2627 (☧).

See also: Christian symbolism, Christogramde:Labarum