The Fantasia on a Theme by Thomas Tallis was written in 1910, and first performed at the Three Choirs Festival that year in Gloucester Cathedral, in a concert along with Elgar's Dream of Gerontius.

No-one knew quite what to expect - though 39 years old, Vaughan Williams was little known at that time - and many people found it strange and even a little disturbing. It is a work of marked contrasts; declamatory yet intimate, passionate yet austere, and a work in which, despite the radiance, shadows still lurk in the corners. It involves three distinct groupings - the full string orchestra, a small and distant string orchestra, and a solo quartet. A mysterious chordal introduction sets the scene for the entry of Tallis's tune on pizzicato cellos and basses; thereafter an A-B-A structure takes shape, the start of the B section being marked by the solo viola with a new segment of the Tallis theme.