The Barddas of Iolo Morganwg, Vol. I., ed. by J. Williams Ab Ithel, , at sacred-texts.com
Ammianus Marcellinus says that "the Bards record the exploits of heroes, in poems, which they sing to the soft sound of the lyre," 1 which is quite in accordance with the practice of the Cymric Bards. He also observes that the Druids were similar to the Pythagoreans, as indeed they were with reference to the doctrine of the metempsychosis.
lxvii:1 Lib. xv. c. 9.