I always was under the impression that halos in paintings are meant to represent light, like rays emanating from a person’s head, giving a visual cue that the character depicted is holy, heavenly, or otherwise divine. But an unnamed but assuredly “well known” American painter puts forth a more interesting theory in this article.
“The first subjects to feel the Renaissance were architecture and sculpture, and this several generations before the days of Cimabue and Giotto, the earliest of painters. Of these subjects architecture came first, as is still evidenced in the magnificent ruins of cathedrals scattered over Europe. I say cathedrals, because everything was saturated with the religious spirit in those days, and the architect expressed his genius in his conceptions of the house of God.
“Later came the sculptor. He gave expression to his art in the images of the saints and other holy characters. The commonest form of expression was life-sized images of the saints, which were set in solemn row about the outside of the churches and cathedrals immediately under the eaves of the building.
“Now, the earliest sculptors soon saw that in a very short time the heads and faces of these figures were soiled and disfigured by action of the driving elements in time of storms; even the hot sun contributed its share in cracking the skulls and faces of the sacred images. Accordingly, to protect them they placed upon their heads a flat wooden disk that extended out far enough to act as umbrella or sunshade, as either was necessary.
“Now, it was several generations before any painters of note arose. These, of the Cimabue-Giotto type, were ignorant, even for that day of ignorance. Of course, following the spirit of the age, they must needs make their subjects holy ones, and the statues standing so invitingly to their hands offered themselves as their first models.
“Thinking, in their wealth of ignorance mentioned, that the wooden disk had something to do with the saintly character of their models, these peasants faithfully copied it into their paintings. In nearly all of the paintings of Comabue and many of those of Giotto, especially his earlier ones, the flat disk is represented, merely as such without any attempt at idealization. Later, however, the painters emphasized the rim and painted the body of the disk a color that barely distinguished it from the surrounding hues.”
So halos are really just misunderstood umbrellas. Somebody needs to add that to Wikipedia.
THE BIRTH OF THE HALO (PDF)
From November 6, 1910