The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, , at sacred-texts.com
The three pillars of memory and history: vocal song; letter; and symbol. A symbol is a form that is understood, and, being understood, shews at sight that that really exists which would require many letters, or much of vocal song, or speech and oration, before it could be properly understood.
There are three symbols: the symbol of number; the symbol of sound or tone, from which is justly shown the voice and tone of harmony; and the symbol of hieroglyphics, which is the form and sign that is understood by its formation; and the blazonry of the arms of nobility, and the arms of nation. The man who knows this art, and will show it authoritatively, is called a herald-bard, and his office and art is to represent history in hieroglyphics, even as the times of the moon are shewn by its visible delineations, and the number of year, month, and day.