Besides being a patron of dramatists (in Wales and London ) and musicians, e.g. his association with Josef Holbrooke in the production of The Children of Don and Dylan , he was himself a writer , the Arthurian cycle giving him the subject of his first play, and, later, the folklore of Wales providing him with material for operatic libretti. Among his works are: Children of Don ( 1912 ), Pont Orewyn ( 1914 ), Lanval ( 1915 ), Dylan ( 1919 ), The Cauldron of Annwn ( 1922 ), The Cauldron of Annwn, including the story of Bronwen ( 1929 ), Five Pantomimes ( 1930 ), Song of Gwyn ap Nudd [ 1913 ]. He had previously published Banners, standards, and badges: from a Tudor manuscript in the College of Arms , and Some feudal lords and their seals , both in 1904 . His last full-length play, which dealt with the emperor Heraclius and his relations with both Christianity and Islam , was produced in 1924 . He was awarded the degree of LL.D. honoris causa by the University of Wales , was President of the Nat. Museum of Wales and a governor of the Nat. Library of Wales . In 1938 he became a trustee of the Tate Gallery . He d. 5 Nov. 1946 in London .