Agnus Dei (liturgy) Agnus Dei (liturgy) In the Mass of the Roman Rite and also in the Eucharist of the Anglican Communion, the Lutheran Church, and the Western Rite of the Orthodox Church the Agnus Dei is the invocation to the Lamb of God sung or recited during the fraction of the Host. The Syrian custom of a chant addressed to the Lamb of God was introduced into the Roman Rite Mass by Pope Sergius I (687–701) in the context of his rejection of the Council of Trullo (692), which was well received in the Byzantine East and called the Quinisext Council, but
Agnus Dei (Barber) to a tension. A similar pattern follows in measures 5 to 8 on the words "qui tollis peccata mundi" (who takes away the sins of the world), moving down on "peccata mundi". The repetition of the call "Agnus Dei" is set as variation of the beginning, intensified by upward leaps of fifths and octaves, and by the solo soprano reaching the highest note of the piece, C-flat. Then the alto takes over the melody, marked "più f[orte] sempre espressivo" (somewhat stronger and always expressive), while the soprano sings "miserere nobis" (have mercy on us) for the first time on a