Composed in 1910 for three distinct string groups (a large string orchestra, a second orchesta comprising the first desk from each section, and a solo string quartet) Vaughan Willliams' Fantasia on a Theme by Thomas Tallis is arguably his best known composition. VW was a scholar of English church music, and Thomas Tallis was a giant of the late renaissance in England and one of the early members of the Chapel Royal.
 
The original Tallis theme is a psalm tune (one of nine) that he contributed to a Psalter from 1567 for the Archbishop of Canterbury. Vaughan Williams included this psalm setting along with the Archbishop's words in the English Hymnal which he edited in 1906. Such was the genesis of the Fantasia.
 
This version for brass ensemble does not attempt to emulate the string orchestra. Rather it reimagines the Tallis Fantasia relying on the rich and contrasting sonorities within the brass ensemble.