Agnus Dei

In the Gospel of John the Baptist sees Jesus approaching and says, behold the Lamb of God, who takes away the sin of the world. The Roman liturgy took his words and set them at the breaking of the bread. The Liber Pontificalis, the old book of papal lives, records that Pope Sergius I, elected in 687 and himself of Syrian descent, decreed that at the time of the fraction the clergy and people should sing Agnus Dei, qui tollis peccata mundi, miserere nobis, and scholars have long connected the innovation with the eastern Christian communities then prominent in Rome, and with Sergius's known resistance to a council that had restricted depicting Christ as a lamb.

The chant accompanied the practical business of breaking the consecrated bread for distribution, and was repeated as long as the fraction took, before settling into the familiar threefold form, twice have mercy on us, and the third time grant us peace, a petition matching the kiss of peace nearby in the rite. In Masses for the dead the older books changed the endings to grant them rest, dona eis requiem, with eternal rest at the third repetition, a variant every listener to the great requiem settings has heard even if they never met it in a liturgy.

As the final sung item of the Mass ordinary, the Agnus Dei closes every complete Mass setting in the Western musical canon, from the anonymous masters of the medieval cycles through Palestrina and Byrd to the concert Masses of the classical and romantic centuries, and composers have habitually saved a particular tenderness for it, the plea for mercy and peace inviting music of quiet rather than splendour.

The dona nobis pacem of Bach's Mass in B minor and the troubled, drum shadowed Agnus Dei of Beethoven's Missa solemnis, marked as a prayer for inner and outer peace, are only the most famous cases of the text drawing from composers a meditation on peace itself. The phrase also named a sacramental. From the medieval period until modern times, wax discs stamped with the image of the lamb, blessed by the pope and called Agnus Deis, were distributed and worn as objects of devotion, an extension of the liturgical image into the pockets of the faithful.

The Eastern liturgies have no equivalent chant at the fraction, but the same scriptural image stands even closer to the centre of their rite, for in Byzantine usage the portion of bread destined for consecration is itself called the Lamb, cut from the loaf with the Baptist's words, so that East and West carry the same verse into the eucharist by different doors.