The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, [1862], at sacred-texts.com
Here is the system of Symbols.
There have been three symbols remembered and preserved from the beginning by the Bards and Sages of the nation of the Cymry; namely,
1. The symbol of word 2 and speech, that is, letter. It is from the symbols that a visible word is formed, and from the words a visible language, and visible vocality.
2. The symbol of harmony and tone, that is, the signs of the sound and utterance of vocal song, and instrumental 3 song.
3. The symbol of number and weight.
The symbols of number are exhibited under the signs of the ten vocal characters of word and speech, that is, the ten characters of the primitive letters, which are kept secret by the Bards of the nation of the Cymry under the obligation of a vow, and may not be divulged to other than a Bard under the sworn vow of life and death. Nevertheless, for the purpose of instructing the common people, the sworn ten characters are not the means, but the trite signs of number, such as are in the memory and knowledge of a
civilized country and nation, and in unison with the sense of civilization, and the three foundations of the sciences of learning, and the three signs of a civilized and scholastic nation.
Here is a description of the symbols, as they are exhibited under the trite signs of number in use by the civilized nations of Belief and Baptism.
1 one, 2 two, 3 three, 4 four, 5 five, 6 six, 7 seven, 8 eight, 9 nine, 0 ten, and placing before the 0 the number which it has, thus, 10 one-ten, 20 two-tens, 30 three-tens, 40 four-tens, 50 five-tens, 60 six-tens, 70 seven-tens, 80 eight-tens, 90 nine-tens, 100 hundred. 11 one-ten and one, or ten and one, 12 one-ten and two, or ten and two, 13 one-ten and three, or ten and three, 14 one-ten and four, or ten and four, 15 one-ten and five, or ten and five, 16 one-ten and six, or ten and six, 17 one-ten and seven, or ten and seven, 18 one-ten and eight, or ten and eight, 19 one-ten and nine, or ten and nine, 20 two-tens, 30 three-tens, 40 four-tens--and one, or two, and two-tens, &c., one being added for every other plurality of tens as far as a hundred; 101 a hundred and one,--a hundred and two, &c., or one and a hundred, two and a hundred, &c., and so for every additional hundred; 101 a hundred and one, 120 a hundred and two-tens, 125 a hundred and two-tens and five, &c., and so for every additional hundred as far as a thousand; and so for every additional thousand as far as a myriad, and for every additional myriad as far as a million, and for every additional million; and so on, in the same manner, as far as buna or mwnda; and on as far as cattyrva; 1 and on as far as rhiallu; 2 and from rhiallu to manred; 3 and from manred
to cyvanred; 1 and from cyvanred to ceugant, 2 which God only knows.
From the "Brith Cyvarwydd," compiled by Anthony Powell of Llwydarth in Tir Iarll, about 1580.
In the Book of Llywelyn Sion thus;--
There are three series of Coelbren symbols, namely, the symbols of language and speech, being twenty-four symbols; the symbols of music and harmony, of which there are seven, namely, a, b, c, d, e, f, g; and they are called the symbols of tone, and the tones of music; and the five symbols of time, namely, , which signify the times of the tones. Where bare tones are exhibited, the times are put over them, but where staves are used, that is, the four staves of music, the times are represented on the staves and intervening spaces.
99:2 Al. "of language."
99:3 Lit. "stringed."
101:1 p. 101 Cattyrva (cad-tyrva) means literally, the crowd of battle.
101:2 Rhiallu, (rhi-allu,) the power of a sovereign; army of a country.
101:3 Manred, (man-rhed,) the elementary particles of creation.
103:1 p. 102 Cyvanred, (cyd-man-rhed,) an aggregate of the elementary particles of creation.
103:2 Ceugant (cau-cant,) an enclosing circle, being the term used by the Bards to denote the infinite space which God alone traverses.
As these several terms were borrowed to represent particular figures in the Numeration Table of the Bards, it would seem that at first they respectively presented to the Bardic eye definite ideas of numbers, such indeed as those which p. 103 were afterwards attached to them. This view is supported by the fact that the Romans considered their caterva as composed of a definite number of men, namely, six thousand.