The halo or nimbus is a device used in art by the Egyptians, Syrians and Romans long before Christianity.
In all cases the halo (circle of light) or nimbus (rays of light) signified identification with the sun god.
The halo was used in images of deceased emperors in Rome, to indicate they now dwell in the paradise of the gods. Later the device was used in representations of living emperors, to show their authority.
The halo hardly appears at all in Christian art prior to the third century — images of God, Christ, angels etc., are obviously who they are, and unadorned — the practice seems to develop when showing a scene from 'real life', Christ talking to the people or sitting on a throne, then it is used to indicate this is no ordinary person.
From the fourth century on, the practice broadened. During the Middle Ages, it took on a life of its own. Living people were shown with square halos, whilst the saints etc., were rounded.
The transfer from pagan to Christian is hardly surprising. In pagan usage, it initially inferred divine status, but by the time of Constantine it was equally used to signify an 'upright' or 'just' or 'noble' person, not necessarily a god or demigod.
Again, there are so many references to light in Scripture that it was almost inevitable that the cross-over would occur.
There is no conferring of halos in Scripture, but there is, of course, tongues of fire that descend on the disciples at Pentecost.
Thomas
