(In early centuries, the consecrated bread had to be broken, divided into small pieces to be given to each of the congregants; however it gradually was supplanted by the consecration of a quantity of small hosts of unleavened bread along with the larger host of the celebrant. The breaking of the bread is still symbolized by the Fraction of the Host of the celebrant.
(In the centuries when the consecrated bread was broken, it was placed by the celebrant on a large Paten, a kind of platter. Once it no longer had that function, the Paten became smaller and began to be used at the offertory of the the host of the celebrant. A vestige of its first use still survives with the celebrant signing himself with the Paten and kissing it before beginning the fraction.)
The celebrant signs himself with the Paten, and then kisses it.
The celebrant breaks the consecrated host into two equal pieces.
He then breaks off a smaller piece, a particle, with which he makes the sign of the cross three times over the chalice of consecrated wine, while saying:
Pax ✠ Domini sit ✠ semper ✠ vobiscum.
r. Et cum spiritu
The peace ✠ of the Lord be ✠ always ✠ with you.
r. And with your spirit.
(The Pax Domini originally was a signal and an invitation to the faithful to exchange the kiss of peace.)
The celebrant then drops the particle into the chalice, praying:
Haec commixtio et consecratio Corporis et Sanguinis Domini nostri Jesu Christi fiat accipientibus nobis in vitam aeternam. Amen.
May this commingling and consecration of the Body and Blood of our Lord Jesus Christ be to us who receive it effectual to life everlasting. Amen.
Striking his breast, the celebrant repeats three times the words of St. John the Baptist:
Agnus Dei, qui tollis peccata mundi: miserere nobis.
Agnus Dei, qui tollis peccata mundi: miserere nobis.
Agnus Dei, qui tollis peccata mundi: dona nobis pacem.
Lamb of God, who takes away the sins of the world, have mercy on us.
Lamb of God, who takes away the sins of the world, have mercy on us.
Lamb of God, who takes away the sins of the world, grant us peace.
At Masses for the dead after the first two invocations is said:
Dona eis requiem.
Grant them rest.
and after the third:
Dona eis requiem sempiternam.
Grant them eternal rest.
(Originally, the Agnus Dei was a chant to accompany the fraction, the breaking of the bread.)