LABARUM

sacred military standard of the Christian Roman emperors, first used by Constantine I in the early part of the 4th century AD. The labaruma Christian version of the vexillum, the military standard used earlier in the empireincorporated the Chi-Rho, the monogram of Christ. The 4th-century historian Eusebius, in his Life of Constantine, describes the labarum as a long gilded pike, from whose crossbar hung a jeweled square of purple cloth; atop the spear a golden wreath enclosed the sacred monogram. According to Eusebius, 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 documented by coins issued at Constantinople (now Istanbul) after Constantine's victory over Licinius in 324.