In reply to your query on Llyn Celyn in the Treweryn Valley, I was going to quote the whole englyn, but Geraint Jones beat me to it! All I can add is that, if you want to see the englyn in print, it is to be found in The Oxford Book of Welsh Verse, (Parry, T., ed. The Oxford Book of Welsh Verse. Oxford: Clarendon Press, 1962.) on page 534. John Williams, Saudi Arabia.