The priest breaks off a small part of the consecrated Host during the Agnus Dei, which is after the Lord’s Prayer and the sign of peace, but before holy Communion. The rubrics specify: “Then he takes the Host, breaks it over the paten, and places a small piece in the chalice, saying quietly: ‘May this mingling of the Body and Blood of Our Lord Jesus Christ bring eternal life to us who receive it.’” The celebrant breaks the bread because that is what Jesus did at the Last Supper, and on that very night Jesus said, “Do this in memory of me.” Furthermore, the priest drops that little piece of the consecrated Host into the chalice with the Precious Blood to signify the unity of the Church. As the General Instruction of the Roman Missal explains: “The gesture of breaking bread done by Christ at the Last Supper, which in apostolic times gave the entire Eucharistic Action its name, signifies that the many faithful are made one body (1 Cor 10:17) by receiving Communion from the one Bread of Life, which is Christ, who for the salvation of the world died and rose again” (No. 83).