The Byrd Edition Volume 5. Edited by Philip Brett. As Byrd emphasised in his precise description of their contents, Gradualia is primarily a collection of pieces proper to the Mass and most of the chief feasts of the Roman Catholic calendar. This volume contains the first sections of Book 1, in which the composer attempted to cover all the occasions when a Marian Mass was required, either on feast days of the Virgin or for the customary Saturday observance of the Votive Mass. ?