labarum
Cross devised and used by Constantine. Edward Gibbon in The Decline and Fall of the Roman Empire refers to the principal standard which displayed the triumph of the cross, and being an obscure but celebrated name derived from almost all the languages of the world. It is described as a long pike intersected by a transversal beam. A silken veil hung down from the beam and the summit of the pike supported a crown of gold which enclosed a mysterious monogram expressive of the figure of the cross and the initial letters of the name of Christ. The safety of the labarum was entrusted to fifty guards, making them secure and invulnerable to the darts of the enemy. Licinus felt and dreaded the power of this consecrated banner in the second civil war, the sight of which animated the soldiers of Constantine. Later it was deposited as a venerable but useless relic in the palace at Constantinople. Medals of the Flavian family carry the labarum. A medal of the Emperor Constantine displayed the cross with the memorable words “by this sign though shalt conquer.”