/lab"euhr euhm/, n., pl. labara /-euhr euh/.1. an ecclesiastical standard or banner, as for carrying in procession.2. the military standard of Constantine the Great and later Christian emperors of Rome, bearing Christian symbols.[1650-60; < LL, of obscure orig.]
* * *▪ Roman militarysacred military standard of the Christian Roman emperors, first used by Constantine I in the early part of the 4th century AD. The labarum—a Christian version of the vexillum, the military standard used earlier in the Roman Empire—incorporated the Chi-Rho, the monogram of Christ, in a golden wreath atop the staff. The flag was made of purple silk (purple dye being at this time a rarity derived from a shellfish of the genus Murex) richly embroidered with gold. Although usually suspended from a horizontal bar, it appears to have been displayed occasionally by fastening one of its sides to its staff. In the Middle Ages the pastoral staff of a bishop often had attached to it a small purple scarf known as the vexillum, supposedly derived from the labarum.According to the 4th-century historian Eusebius (Eusebius of Caesarea), in his Life of Constantine, before the victory over Maxentius (312), Constantine saw a sign of the cross in the sky and the words “in this sign thou shalt conquer” and used it as a talisman in battle. Dating of the labarum is attested by coins issued at Constantinople (now Istanbul) after Constantine's victory over Licinius in 324.
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