A.O.H. Jarman 's main fields of research were the Myrddin/Merlin legend, the origins and development of which he traced in a series of important articles and lectures (including the British Academy Sir John Rhys Lecture in 1985), medieval Welsh tales, and the Welsh Arthurian legends in particular, and early Welsh poetry. He published a standard edition of the Black Book of Carmarthen in 1982 and an English translation of ‘Y Gododdin’ with a full critical commentary in 1988, 1990. He also worked in other areas, Geoffrey of Monmouth , eighteenth-century scholarship, the Morris brothers of Anglesey , and he contributed a chapter, ‘Wales as part of England, 1485-1800’ to The Historical Basis of Welsh Nationalism, ed. D. Myrddin Lloyd (1950). He was the editor of Llên Cymru from 1961 to 1986 and of Y Ddraig Goch from 1941 to 1946. All his work is characterised by a keen intellect, attention to detail and clarity of expression. There is a bibliography of his publications to 1991 in Ysgrifau Beirniadol 18 (1992), together with an essay by J. E. Caerwyn Williams and a photograph. Fred Jarman was a committed nationalist and a supporter of Saunders Lewis since his college days. He was a conscientious objector on nationalist grounds during World War 2 and spent periods in Walton and Stafford prisons. He was a man of strong convictions who was respected for his unflinching principles. Never an easy conversationalist, he was, nevertheless, good company when he was able to relax with friends, an authority on good food and wines and a regular visitor to France.

Fred Jarman married Eldra Roberts in 1943 and they had two daughters. Eldra Jarman , who was proud of her gypsy lineage, was an accomplished harpist and co-author with her husband of Y Sipsiwn Cymreig: teulu Abram Wood (1979), revised and expanded English version, The Welsh gypsies: the children of Abram Wood (1991). Fred Jarman died in Cardiff Royal Infirmary 26 October 1998 and was cremated at Thornhill Crematorium, Cardiff , 30 October. Eldra Jarman died aged 83 in 2001.