Gerald of Wales* (1197 CE: Book 1, Chapter II) notes that there is a well at the very top of Cadair Arthur ("Arthur's Chair") which is square, has no stream running from it, and an occasionally contains trout. Arthur's Chair is a somewhat Romantic name for the main two peaks of the Brecon Beacons near Cilwhybert and the col/cwm between them. The description given by Gerald is certainly convincingly like that in the Historia, other than the obvious fact that the Historia doesn't mention the mountaintop location. However the wonder was also mentioned by Geoffrey of Monmouth (See Wonder 1 Myth, Note), who sited it in Scotland for narrative reasons. Gerald had an bi-polar attitude to Geoffrey's work (see, for example, Crick*), and the description he gives seems a little too casual - not only would a spring on a mountain top seem pretty odd, but the fish getting there would seem to deserve more comment. This might, accurate or not, be a little one-up-manship on Gerald's behalf.