Introitus

The Introitus, also known as the Introit (from the Latin intro-), is the opening of the Requiem Mass.

Structure
The Introit can contain the following movements:
 * Requiem Aeternam
 * Kyrie

Requiem Aeternam
This is the opening movement of any Requiem Mass. It is a simple invocation, asking for safe delivery of the dead into heaven.

Et lux perpetua luceat eis. Te decet hymnus, Deus, in Sion, Et tibi reddetur votum in Jerusalem Exaudi orationem meam Ad te omnis caro veniet.''
 * ''Requiem aeternam dona eis, Domine.

And let perpetual light shine upon them A hymn, O God, becometh Thee in Zion And a vow shall be paid to thee in Jerusalem Hear my prayer All flesh shall come before you.
 * Eternal rest give unto them, O Lord

Kyrie
The Kyrie is often considered its own section, yet follows immediately after the Requiem Aeternam in the Liturgy, and therefore is considered an Itroitus movement. Because of this, the Requiem Aeternam and Kyrie are often in one movement. It is the only non-Latin text in the tradition Latin Requiem Mass, originally written in Greek.

Christe, eleison! Kyrie, eleison!''
 * ''Kyrie, eleison!

Christ, have mercy on us. Lord, have mercy on us.
 * Lord, have mercy on us.