The lábaro is an antigo banner of war, for Christians is also a religious symbol according to a legend, the Roman Emperor Constantine (Flavius Valerius Aurelius Constantinus Augustus) saw in a dream or in a mystical vision about the noon sky the figure of a chrism or monogram of Christ with the inscription HOC sign VlNCES (with this sign conquer), and joined his Labarum before the battle. Since it is also a name for the banner with the sign of Christ.