Idris is a mythical figure in Welsh tradition, supposed to have been at once a giant, a prince, and an astronomer. On the summit of Cader Idris in Wales may be seen his rock-hewn chair, and an ancient tradition told that any Welsh bard who should pass the night upon it would be found next morning either dead, mad, or endowed with supernatural poetic inspiration. The gigantic size of the chair is alluded to in Tennyson's Geraint and Enid.