Rachel Bromwich was a distinguished Celtic scholar whose magnum opus was Trioedd Ynys Prydein: the Welsh Triads, an index of legendary characters, arranged in groups of three, a characteristic feature of the traditional lore of Britain and Ireland since earliest times. In medieval Wales, asociety in which oral instruction was the chief means of conserving and transmitting bardic culture, the triad served as a mnemonic device for cataloguing facts and ideas. Bromwich's book, first published in 1961, is an invaluable dictionary of Welsh and British legend; a splendid third edition appeared in 2006.
Working from a collation of manuscripts of the 13th and 14th centuries, she provided a translation of the texts, together with a commentary, thus throwing a great deal of light onallusions to heroes, places and events from the distant British past. In so doing she elucidated many of the more problematic references in early Welsh poetry, particularly that written in"the Old North" – what are now parts of southern Scotland and northern England.
The erudition and meticulous scholarship displayed in her edition of the Triads was typical of all her work. She brought to it a formidable intellect and wide reading in the literatures and cultures of the Celtic countries which had begun long before she had personal contact with any of them.
She was born Rachel Amos in Brighton, Sussex, in 1915, but spent her early childhood in Egypt, where her father was a barrister and Professor of Law. On his retirement in 1925 the family returned to England, settling in Cumberland, a county with old British associations which she was later to study as belonging to the traditions of "the Old North".
At Newnham College, Cambridge, she took the first part of the English Tripos in 1936 and the second part, consisting of Anglo-Saxon, Norse and Celtic, two years later, graduating with a First in both. The principal influence on English studies in Cambridge at the time was HM Chadwick, the foremost authority on the archaeology and languages of early Britain. It was his pupil, Kenneth H Jackson, who persuaded Rachel Amos to go on to the University College of North Wales, Bangor, to study Welsh under Sir Ifor Williams.
The Second World War interrupted her studies at Bangor. Her husband, John Bromwich, a lecturer in Anglo-Saxon at St John's College, Cambridge, was posted to Northern Ireland, and she joined him there in 1940. For a while she was able to attend the Old Irish classes of Professor Michael O'Brien at Queen's University, Belfast, but when Bromwich was sent overseas she returned to Cumbria with their child.
In 1945 she was invited to teach Old Welsh and Old Irish as part of the English Tripos at Cambridge, and there she was to remain for the rest of her academic career. Among her first publications were studies of Gaelic tradition in 18th-century Ireland, including an essay on the "Lament for Art O'Leary", and of the Arthurian tradition in Scotland and the Breton Lays. Her chapter on the drowned kingdoms of Cantre'r Gwaelod and Ker Ys in The Early Cultures of North-West Europe (The HM Chadwick memorial volume, 1950) is a model of lucidity and comparative scholarship. She was made University Reader in Celtic Languages and Literatures in 1973 and, in the year following, held the Sir John Rhys Fellowship at Oxford, where she was one of the first women to be elected Fellow of Jesus College.
Her work on Dafydd ap Gwilym,generally considered to be the outstanding Welsh poet of the medieval period, is much admired. In Tradition and Innovation in the Poetry of Dafydd ap Gwilym (1964) she demonstrated the French influences on his work, a theme she continued to explore innumerous essays collected under the title Aspects of the Poetry of Dafydd ap Gwilym in 1986. For readers with no Welsh she translated a generousselection of Dafydd's poems which appeared as a Penguin paperback in 1985. She was among those who in 1984unveiled a memorial stone to Dafydd ap Gwilym in the churchyard atTalley in Carmarthenshire in thebelief that the poet was buried there and not, as is the traditional belief, at Strata Florida.
As a tribute to her old teachers, Sir Ifor Williams at Bangor and Sir Idris Foster at Oxford, she edited The Beginnings of Welsh Poetry (1972) for one and (with R Brinley Jones) Astudiaethau ar yr Hengerdd (1978) for the other. The second of these consisted of essays written by members of the group devoted to the study of the earliest Welsh poetry in Oxford.
On her retirement in 1976 Rachel Bromwich went to live in Bethesda, the former slate-quarrying village in Gwynedd, where she renewed her contact with the University College of North Wales at Bangor by accepting an Honorary Professorial Fellowship in the Department of Welsh. The University of Wales awarded her the honorary degree of DLitt in 1985 and in the same year the 13th volume in the prestigious series Ysgrifau Beirniadol, including a full bibliography of her writings, was presented to her.
Her last years were spent in Aberystwyth, where she worked indefatigably at the National Library of Wales and the University of Wales Centre for Advanced Welsh and Celtic Studies.
Rachel Amos, Celtic scholar: born Hove, Sussex 30 July 1915; Lecturer and Reader in Celtic Languages and Literatures, University of Cambridge 1945-76, then Emeritus; married 1940 John Bromwich (deceased; one son); died Aberystwyth, Ceredigion 15 December 2010.