Dyson studied piano with the legendary Kathleen Long at the Royal College of Music and it was on hearing her teacher play baroque music on the piano that she became interested in the music of that period. She then discovered the fine collection of early keyboard instruments at the RCM which further inspired her interest. Eventually she bought her own Goble harpsichord and gave her first Wigmore recital on that instrument in 1941.
During the Second World War, she did auxiliary nursing under the Red Cross, taught music to evacuee children and made endless tours giving concerts in factories, military camps and hospitals.
After the war she continued her career as both pianist and harpsichordist. She played piano concertos with most of the main orchestras in the UK and gave frequent solo recitals on both instruments. She also undertook many European tours sponsored by the British Council and made regular broadcasts from the BBC for over 30 years, many of which were first performances of works by contemporary composers for the early keyboard instruments. She also made numerous recordings for the BBC Archives on instruments from famous collections which included the Victoria and Albert Museum and the Colt Clavier Collection.
In the late Forties Dyson was involved for some time with the Leith Hill Festival and valued the friendship of its founder, Ralph Vaughan Williams. For some time she served as the festival's librarian and would recall the occasion when Vaughan Williams telephoned her to ask about some of the Haydn oratorios, adding: "Don't forget we're meeting at 10 o'clock tomorrow morning when we're going to rub out the Creation!"
Dyson returned to the RCM in 1964 to take up professorships in both harpsichord and piano and a lectureship in the history of early keyboard instruments. It was during this time that she took her students to visit the famous collections of early keyboard instruments and so inspired them to take up the study of baroque music for themselves; among those who are now firmly established in the field are Melvyn Tan, Sophie Yates, Robert Woolley and many others. She was awarded a Fellowship in 1980 and retired in 1987 after 23 years of service. Her students adored her and many kept in touch right up to the present.
Dyson's lecturing activities also extended abroad where she lectured in French at the World Forum of Harpsichord in Paris and in German to the Telemann Society in Hamburg. She also represented the UK as adjudicator at the International Fortnight at Bruges. She contributed articles to a number of learned journals and to the 1979 edition of The Oxford Companion to Music.
As a soloist she made a number of recordings which included Herbert Howells works for the clavichord to celebrate the composer's 90th birthday. She also made recordings with the bass singer and harpsichordist Peter Medhurst with whom she shared a happy musical partnership for the last 20 years; these included an album of Schubert songs recorded at the Colt Clavier Collection. One of their most recent recordings For Two To Play was of all the double harpsichord works up to the time of Mozart when the harpsichord was superseded by the piano. Medhurst told me: "She was my mentor and it was such a joy to work with her. She was so spontaneous and a brilliant keyboard player, and she had such rhythmic point. Whatever instrument she played - great music came out."
She was married to the military historian Edward Thomas, nephew of the poet of the same name who was killed in the First World War. She loved travelling with her husband as he revisited many of the places abroad where he was in military intelligence, including Thailand in 1995, the last journey they made together. He died in 1996.
Dyson appeared for many years in the Haslemere Festival of Early Music, and its Musical Director, Jeanne Dolmetsch, recalled attending her 80th birthday party in March this year: "She was in sparkling form. She will be remembered for intimate, witty and informative lectures, her wonderful accompanying and her skill in improvisation. She was my musical mother!"
As a person she was charming, unaffected and modest despite the fact that she had an incredibly scholarly mind. She was also generous towards other artists - a rare quality among musicians.
In recent years she taught regularly at the Dolmetsch Summer School, and confessed it was one of her favourite undertakings because clearly she had a special empathy with the young. It was here, on the last afternoon of the course, that she suffered a fatal heart attack after a wonderful week in which she had been full of her usual enthusiasm. As Jeanne Dolmetsch put it: "Ruth Dyson's life was rather like a piece of music which bubbles over with excitement and ends in a perfect cadence. That is how she would have wanted it."
Barbara Ruth Dyson, keyboard player and teacher: born London 28 March 1917; married 1964 Edward Thomas (died 1996; one step-son, one step-daughter); died Guildford, Surrey 16 August 1997.