His trilogy of novels, Cwm Hiraeth, generally thought to be his finest achievement in prose, is based on the story of his own family over three generations, and has some claim to be the most outstanding example in Welsh of the roman-fleuve. The first, Y Briodas ("The Wedding", 1969) deals with life in the Rhondda in his parents' day, from 1900 to 1915, when the valley was a cauldron of industrial unrest which was to boil over in the Tonypandy Riots of 1910.
In Y Siol Wen ("The White Shawl", 1970) he described the General Strike of 1926 and in Dyddiau Dyn ("A Man's Days", 1973), the economic depression which ravaged South Wales in the 1930s. These events are seen through the eyes of the author's Uncle Sion, a poet and thinker who turns against the chapel and the Lib-Labbery of William Abraham (Mabon), the Rhondda miners' leader, to embrace socialism and the ideals of the South Wales Miners' Federation, only to grow disillusioned and bitterly opposed to the materialism of the Labour Party and the hegemony of its local representatives.
Williams's birth and family background in the Rhondda, the most famous of the coal- bearing valleys of South Wales, marked him indelibly and, although he was to spend the years from 1931 to 1941 away from the valley, notably at Christleton in Cheshire, to which his parents had moved in search of work and where he was intensely unhappy, it was to the Rhondda that he returned in his imagination and there, in 1941, that he was given his first pastorate - at Ainon, a Baptist chapel in the mining village of Ynys-hir.
His five years at Ynys-hir were the making of him as a poet. Hitherto he had worked at a variety of menial jobs and studied intermittently at the University Colleges of Swansea and Bangor. A conscientious objector on Welsh Nationalist grounds, he had served for a while with a Quaker ambulance-unit during the bombing of Liverpool. Of a rebellious nature, he was often in trouble with his denomination on account of his pacifism, political nationalism, unorthodox theological views, and Bohemian life- style. He had a fondness for good wine, expensive restaurants, fast cars, the theatre and good company into old age, and his profligate attitude to money was legendary. But the call to the Christian ministry had always been strong in him and, blessed with good looks and a voice that were compared with Richard Burton's, he became a powerful preacher and a gifted reader of poetry on the Welsh Home Service of the BBC.
His development as a poet was encouraged through his friendship with the Cadwgan Circle, a coterie of Welsh writers and intellectuals who included Gareth Alban Davies (later Professor of Spanish at Leeds), J. Gwyn Griffiths (later Professor of Classics and Egyptology at Swansea) and Pennar Davies (later a distinguished theologian and Principal of the Independents' College at Brecon and Swansea). They met at the Griffithses' home at Pentre in the Rhondda, where they discussed contemporary European literature and, in particular, the need to liberate Welsh literature from the puritanical shackles and lyrical niceties imposed on it by the eisteddfodic tradition. What Williams learnt in these discussions was to prove more important to him than the scant formal education he had received. Huxley, Orwell and Auden were among his heroes. He was also a close associate of Kitchener Davies, the dramatist and pioneer of the Welsh Nationalist cause in the Rhondda.
Although Williams was always more than a mere eisteddfodic writer, and was usually ready to poke fun at the Eisteddfod's conservative standards and more absurd rituals, it was at the National Eisteddfod that he first came to prominence as a poet. He won the Crown competition in 1946 with his poem "Yr Arloeswr"("The Pioneer") and again in 1964 with "Y Ffynhonnau" ("The Springs"). The second of these, a long poem in the free metres (the Chair is awarded for a poem in the strict metres), is about tradition and its renewal in Rhondda society, and many readers have found it the most moving and memorable of all his works. He published nine volumes of verse, including one in English, and his Collected Poems appeared in 1991.
Leaving Ynys-hir in 1946, he held pastorates in Resolven and Pont-Iliw in the Swansea Valley for the next 13 years, and spent another at Rhyl on the coast of North Wales. While at Pont-Iliw he had the pleasure, at a local eisteddfod, of presenting a recitation prize to the young Sian Phillips.
But he then turned his back on the Baptist ministry and accepted an invitation to join Granada Television in Manchester, one of the first ministers to find a career in the new medium. There, on shoestring budgets, he produced trail-blazing Welsh-language programmes in which his gifts as impresario and broadcaster were allowed to flower. He also wrote television scripts, one of which, about Dietrich Bonhoeffer, was shown in Germany, the first Welsh- language television play to be broadcast on a foreign network.
Besides his trilogy, Williams published seven other Welsh novels between 1972 and 1988, and one in English, including Breddwvyd Rhonabwy Jones ("The Dream of Rhonabwy Jones", 1972), a light-hearted send-up of the Assembly of Bards of the Isle of Britain, of which he was a life member by virtue of his having won the Crown; Apolo (1975), set in the world of television before Cardiff became known as "media city"; Amser i Wylo ("A Time to Weep", 1986, for which he won the Daniel Owen Prize), about the Senghenydd Explosion of 1913, the greatest pit-disaster in the annals of British mining; and The Angry Vineyard (1975), a fictional account of the Merthyr Rising of 1831 and the execution of Dic Penderyn, "the first martyr of the Welsh working class".
From 1980 to 1986, despite suffering a stroke in 1981 which physically incapacitated him for the rest of his life, Williams edited the current affairs magazine Barn ("Opinion"), bringing to it his journalistic flair, wide reading and keen interest in music and the visual and performing arts. A volume of his autobiography appeared as Gorwelion ("Horizons") in 1984.
Robert Rhydwenfro Williams, poet and novelist: born Pentre, Glamorgan 29 August 1916; married 1943 Margaret Davies (one son); died Merthyr Tydfil, Mid Glamorgan 2 August 1997.