A London Symphony is the second of Vaughan Williams's nine symphonies. Premiered in March 1914 on the eve of the Great War, it enshrines all the glittering brilliance of the pre-war world and, in retrospect, is its epitaph. It was the composer's own favourite of his symphonies and he described it as a "Symphony by a Londoner." Although the Symphony is loosely programmatic, it does not represent the physical body of London, but the spirit of a great city. The spirit and movement of dance is central to much of William Mathias's music. Pieces directly inspired by dance include the Dance Overture (1962), the Invocation and Dance (1961) and the present Celtic Dances, written in 1972 to mark the 50th anniversary of Urdd Gobaith Cymru. Mathias's use of dance is not superficial; on the contrary it reminds us that in earlier times dance was associated with religious fervour. The word ‘Celtic’ had many connotations for Mathias when he came to write this piece. He wrote, "the music is intended to evoke an area of feeling largely associated with the mythological past, even though such an idea is here expressed in terms of our own time. Rite and magic, jewelled colours, the spirit of play, wistfulness, lyrical warmth, and (above all) rhythmic vitality - these are all qualities associated with Celtic arts and tradition, and they were present as part of that area of experience which prompted the composition of this work."

The National Youth Orchestra of Wales under Owain Arwel Hughes performed both of these works at the Welsh Proms in August 2008 and also at Birmingham Town Hall. “ superbly paced and beautifully sonorous, it was intensely moving and really quite marvelous" (Birmingham Post)