The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, , at sacred-texts.com
p. 222 p. 223
The Circle of Abred, in which are all corporal and dead existences.
The Circle of Gwynvyd, in which are all animated and immortal beings.
The Circle of Ceugant, where there is only God. The wise men describe them thus, in three Circles.
222:1 p. 223 Some persons, and among them M. Henri Martin, the celebrated French Historian, are of opinion that the three Circles of existence are represented in the old stone enclosures of the Bards, such as Avebury, and in the wheels observable on ancient British coins.