According to the 9th Edition of National Anthems Of The World
, this song, which is written in 3/4 time, was "First sung at the famous Llangollen Eisteddfod of 1858, and now regarded as having the status of a National Anthem. It is also sung as an anthem in Britanny, to a Breton version by J. Taldir." The version included in this book has English versification by W.S. Gwynn Williams and is arranged by him and W.L. Reed (co-editor of the book) "by permission of the Gwyn Publishing Co", copyright 1950.
Alexander Baron - London, England, for above 2