The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, , at sacred-texts.com
O I W are the three letters, and in very old books O I U, because U was used instead of W, in the olden times. It is the secret word of the primitive Bards, which it is not lawful to speak or utter audibly to any man in the
p. 66 p. 67
world, except to a Bard who is under the vow of an oath. The letters may be shown to any one in the world we like, without uttering the vocalization, which, under the protection of secrecy, is due to them, though he be not under an oath; but should he utter them in speech audibly, he violates his protection, and he cannot be a Bard, nor will it be lawful to shew him any more of the secret, either in this world that perishes, or in the other world that will not perish for ever and ever. 1 Sion Bradford. 2
67:1 p. 66 The non reception of a perjured Bard in the world of bliss is likewise dwelt upon by Sion Cent;--
It is not meet for a godless man,
Who will swear, divulging God,
To go into the fair manor,
Yonder in heaven, without being turned back.
67:2 p. 67 Sion Bradford was admitted a disciple of the bardic chair of Glamorgan in 1730, being then a boy. He presided in the same chair in 1760, and died in 1780.