As applied to the Christian liturgy, a book containing the words and music for the chants sung during the celebration of Mass or the Divine Office. Several types of choir-book evolved during the Middle Ages. A Gradual contains all the chants sung by the choir during the celebration of the Mass. These normally include the antiphons for the Introit (opening phrase), Offertory and Communion chants, as well as the gradual (an antiphon or response sung between the reading of the Epistle and Gospel), after which the book was named. The Gradual was usually written in large format so that it could be placed on a lectern in front of the choir and be read by all the members. Lines of musical notation usually alternate with those of the text and with dense passages of instructions, written in smaller script. The organization of the Gradual is similar to that of the MISSAL in that the chants are arranged in four parts according to the sequence of the liturgical year: the Temporal, Sanctoral and the Common of Saints, as well as the fixed chants for the Ordinary of the Mass (the Kyrie, Gloria, Credo, Sanctus and Agnus Dei). Owing to their large size the books were sometimes separated into different volumes, for example the Kyriale, a choir-book containing only the fixed chants, the Versary, containing the versicles of the chants sung between the reading of the Epistle and the Gospel, and the Responsorial, with the graduals, sequences, offertories, alleluias and responses sung by the choir. Other variants were also developed, such as the Sequentiary containing the hymns sung by a soloist between the alleluia and the Gospel lesson. A Proser is a Sequentiary with only the text of the hymns, the musical notations being either omitted or provided in the margins. A Troper contains tropes or additional songs that were added to chants for the Mass or the Divine Office.
See the Abbreviations for further details.
