(1893–1985). Welsh-language academic, poet and writer born in Wallasey, Merseyside. He was a founder of Plaid Genedlaethol Cymru, of which he became first president. Convicted for involvement in the fire at Penyberth ‘bombing school’ in 1936. His radio speech Tynged yr Iaith (‘the fate of the language’) in 1962 inspired the forming of Cymdeithas yr Iaith Gymraeg.