The sequence (one of which will be recited, or preferably sung on the Feast of Pentecost) is thought to have begun (around the 9th century) as a genre of poetry when Roman chant was flourishing and spreading across Europe. As Roman chant was intended primarily as a musical meditation upon the Word of God, so the Sequence was intended as a musical, meditative extension of the Alleluia verse.
The use, singing, and placement of the Sequence within the Mass and the Divine Office has experienced a long and changing history. The Church now recognizes, and uses, four Sequences: Easter Sunday (Victim paschal laudes); Pentecost Sunday (Veni, Sancte Spiritus); Body and Blood of Christ (Lauda, Sion, Salvatorem); and, Requiem Masses (Dies irae).
The 2011 General Instruction of the Roman Missal specifies that the Sequence is now to be sung before the Alleluia. This placement preserves a stronger connection between the Alleluia and the Gospel, and transforms the Sequence into a more contemplative meditation on the mystery of the day in preparation for the proclamation of the Gospel. The assembly remains seated, in a posture of meditation or contemplation. (For this reason, the assembly should be adequately prepared ahead of time to anticipate the insertion of the Sequence on these feasts.) As already stated, the Sequence is intended to be sung; another reason the assembly, and choir, should be prepared for the Sequence. (Source: USCCB, Committee on Divine Worship Newsletter: Volume XLVIII)
Listen to two different settings of the Sequence, one ancient,
and one new.