Ever more treasures are turning up in the Sacred Music archives.
This is from a 1988 article by Msgr. Hayburn. It is a short history of chant editions:
Pope Gregory XIII adopted a change of policy. On October 25, 1577, he engaged G. P. Palestrina and Annibale Zoilo to prepare a new edition which would conform to the changes in the texts of the Pius V books. The purpose of this minor work was to adapt the text to the melodies, but not to change them. However, these two composers altered the melodies according to humanistic reforms, which considered it a barbarism to have several notes on syllables following the tonic accent, or long notes over the grammatically short syllables and vice versa. They eliminated the long vocalises of the gradual and the Alleluia verses. Moreover, changes were made to place the melodies in agreement with the accentuation and quantity of the syllables. After an investigation, originated by Fernanado de las Infantas and Canon Boccapadule, the pope terminated the work. Palestrina had done only the Sunday Masses of the Graduale.
