1911 Encyclopædia Britannica/Labarum

LABARUM, the sacred military standard of the early Christian Roman emperors, first adopted by Constantine the Great after his miraculous vision in 312, although, according to Gibbon, he did not exhibit it to the army till 323. The name seems to have been known before, and the banner was simply a Christianized form of the Roman cavalry standard. Eusebius (Life of Const. i. 31) describes the first labarum as consisting of a long gilded spear, crossed at the top by a bar from which hung a square purple cloth, richly jewelled. At the upper extremity of the spear was a golden wreath encircling the sacred monogram, formed of the first two letters of the name of Christ. In later banners the monogram was sometimes embroidered on the cloth. A special guard of fifty soldiers was appointed to protect the sacred standard. The derivation of the word labarum is disputed; it appears to be connected with the Basque labarva, signifying standard. See Flag.