The old Welsh tune, Llwyn Onn, known in the English-speaking world as Ash Grove, is over 200 years old, and has been used with the hymn lyrics "The Master Has Come" and "Let All Things Now Living." Regardless what title you know it by, it is a wonderful and beautiful tune.
This piece was originally written for piano, then expanded for organ, then rewritten in a different key for string orchestra, and now violin and cello duet.
The violin plays sixteenth-note arpeggios nearly throughout, while the cello has the melody all the way through.
FANTASIA ON ASH GROVE, for violin and cello duet by Tom Kirkland, comes in a pdf file of 263K, with a five-page score, one three-page part, one two-page part, and a license page, eleven pages in all. Performance time should be approximately 3:40.