This seems to have been the composer’s only piece (surviving complete) for twelve voices in three choirs. Guerrero had it printed twice, first in 1589 and again in his final collection (1597). Two lone high voices begin; at ‘Tres sunt’ three voices are exposed on their own. At ‘Plena est omnis terra …’ the grand tutti join in massive chords. The Trinitarian symbolism is obvious. Here different choral and instrumental groups enhance the separation of the three choirs and their dramatic potential.
from notes by Bruno Turner ę 1999