Byrdís work probably dates from the late 1570s. It is perhaps his only composition to exploit a high G sharp, a note that did not exist on most keyboards of the time. The composer may therefore have written it for a special instrument or a special patron. Could this be why it is called Tregianís Ground in the FVB? Indeed, only Nevell calls it Hugh Ashtonís Grownde. The two titles need not be incompatible since the piece could have been written by Byrd for a member of the Catholic Tregian family, but built on Hugh Astonís bass.
This Ďlongí ground (constructed on a repeating 12-bar bass pattern) in Aeolian A minor is one of Byrdís finest and most harmonically expressive works, balancing elaborate keyboard figuration and cogent contrapuntal discourse. There are twelve variations. The first five unfold gradually, with increasingly rich harmonies and subtle cross-rhythms until, at the end of Variation 5, the quavers break loose; the triplets of Variation 7 continue to carry the music forward. Variation 9 is the most closely argued in polyphonic terms; indeed, it is almost argumentative in nature. In Variations 10 and 11 the quavers run freely again and the work ends with a richly harmonised statement of the bass tune, finally exploiting the lowest part of the keyboard. Thomas Tomkins, an excellent judge of pieces, included this ground on his first list of Lessons of worthe, and himself wrote a ground on the same bass, unfortunately now lost.
from notes by Davitt Moroney © 1999