This monogram has been supposed to have been adopted from the celebrated Labarum, or battle-standard of Constantine, which bore this sacred figure. This was derived in turn, it was feigned, from the image which the imperial convert saw, or thought he saw, traced in the sky in characters of fire brighter than the noon-day sun, before the battle of the Milvian Bridge. Probably a solar halo of unusual splendour was magnified by the eager imagination of Constantine into a token of divine assistance, and the legend Ἐν τούτῳ νίκα was an after addition of the credulous historian. The Christian emblem, according to Prudentius,[448] was worn upon the shields and helmets of the whole army as well as on the imperial standard; “and so,” says Milman, “for the first time the meek and peaceful Jesus became a God
of battle; and the cross, the holy sign of Christian redemption, a banner of bloody strife.”[449]
Probably there is allusion to the above mentioned legend in the following inscription from Bosio:
IN HOC VINCES
SINFONIA ET FILIIS.
In this thou shalt conquer. In Christ. Sinfonia, also for her sons.
On a remarkable sarcophagus in the Lateran Museum is a representation of the monogram[450] supported on a cross and surrounded by a wreath, at which doves are pecking; probably a symbol of the souls of the blessed feeding on the hope of an immortal crown and the sweetness of eternal bliss. Beneath are crouched two soldiers, types, it is thought, of the Christian warriors not yet entered into rest, whose only place of safety is at the foot of the cross; or they may refer to the Draconii, or imperial guard of the Labarum, who, according to Eusebius, passed unhurt amid showers of javelins.
The following enlarged copy of an early Christian seal exhibits the triumph of the cross over the Old Serpent, the Devil, while it is the symbol of salvation to the saints represented by the doves at its foot. In later
art the figures of lions, eagles, falcons, peacocks, doves, and lambs, grouped around the cross, seem to signify its power to subdue evil passions and to inspire holy virtues.