Labarum

A military standard of the Roman empire. It consisted of a long lance cro ed at right angles near the top by a staff, from which hung a small flag or streamer of purple cloth inwrought with gold and precious stones, and bearing the effigy of the emperor. Const an tine the Great, when he embraced Christianity, substituted for that device a crown, a cro , and the initial letters of the name of Christ, and made it the imperial standard.