This 4th volume in the series covers the last period of Lassus’s prodigious activity, choirmaster of Albert V Duke of Bavaria. It begins with Albert’s death in 1579 and thus the crowning of his son William, and ends with the composer’s death in 1594. Old age and disease have barely interrupted a long list of masterpieces. This collection is completed by the motet Musica Dei donum optimi (an exception made to the principle of unreleased works of this biography) published the year of Lassus’s death, a splendid tribute to the music that governed with such power and variety the whole existence of this great name of the Renaissance.