Byrd was an immensely versatile and masterful composer, unequaled in England and some would argue abroad. Quite the musical Shakespeare of Elizabethan England. The Anthem “Alack, when I look back” is an example of his mastery and, in my mind, subtlety of expression.
This subtle dissonance on the word “youth” in the first verse is a good example; it’s as painful as the memory of lost time can be. “Upon my youth that’s passed” is followed by a weak, fleeting cadence, which seems to sum up all that time in a blink. The pathetic fall of “…at last”.
The cadence on “with folly for to die” and “folly kept me blind” (right before the chorus) to me is superbly calm.
The last choral piece of polyphony is a filled with what feels like a heartbreaking regret.
https://www.youtube.com/watch?v=rnRxzpThFNQ (piece starts at 2:37)