The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, [1862], at sacred-texts.com
The sciences of a Herald-bard have been lost, except what is preserved in the art of armory. In primitive times the sciences of heraldry were honourable, and every innate Cymro bore the signs of his lineage, his privileges, and his praiseworthy deeds, and of the praiseworthy deeds of his ancestors; and on that account the bearing of lineage and gentility was called a coat of arms. And when Ovatism was appointed, the sciences of Letter, and the memorial of Coelbren, were improved, and the sciences of heraldry wore abolished, being sufficiently included in the art of a Primitive Bard, namely, Vocal Song, the voice of Gorsedd, and the
sciences of Letter, Coelbren, and Coelvaen, and after that, the Roll of writing. That, namely, the Roll of writing, 1 was obtained by those who first introduced the faith in Christ into this island; that is, it was at that time that the art of elucidating sciences on plagawd skins, in preserved Rolls, became general in the country and among the nation of the Cymry.
165:1 p. 164 The introduction of the Roll is elsewhere specially attributed to Bran the Blessed, father of the renowned Caractacus.