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
Missa Papae Marcelli effect. This was a new technique, using "tonal planning" to replace imitation as the means to keep the music moving forward. The Agnus Dei returns to the imitative polyphony of the Kyrie (the opening of Agnus Dei I repeats that of the Kyrie). As was frequently done in the 16th century, Palestrina adds an extra voice in Agnus Dei II, making seven for this movement, in which is embedded a three-part canon that begins with the head-motive. Missa Papae Marcelli Missa Papae Marcelli, or Pope Marcellus Mass, is a mass "sine nomine" by Giovanni Pierluigi da Palestrina. It is his