A few weeks ago, we posted a perfect Canon by Giovanni Maria Nanino (d. 1607), who was a colleague of Palestrina. Here is a Live Recording by a volunteer choir. The score scrolls by as the singers perform it. It was recorded yesterday at Mass.
Pope Saint Paul VI (3 April 1969): “Although the text of the Roman Gradual—at least that which concerns the singing—has not been changed, the Entrance antiphons and Communions antiphons have been revised for Masses without singing.”