What is a "sequence" ?

If you are following the daily Mass readings (https://universalis.com/mass.htm), you may have noticed a “new” element inserted before the Gospel acclamation: a hymn called the sequence.

The sequence (sequentia in Latin) is the name of the liturgical hymn of the Mass which is sung in connection with four Christian feasts: Easter (hymn Victimae paschali laudes), Pentecost (hymn Veni Sancte Spiritus), Corpus Christi (hymn Lauda Sion) and Our Lady of Sorrows (hymn Stabat Mater). Another traditional sentence is Dies irae for the Requiem Mass. 

​In this Octave of Easter, the ancient sequence Victimae paschali laudes is said or sung. It has been attributed to Wipo of Burgundy, a chaplain to Conrad II who was the German Emperor between 1027 and 1039 (for illustration, in England, King Cnut was crowned in 1016; Shakespeare lovers may appreciate that King Duncan I of Scotland died in 1040, and Macbeth, married to a somewhat ambitious lady, acceded to Scottish throne). Others have ascribed the hymn to Adam of St. Victor, a 12th century poet. 

The sequence narrates the story of death and life locked in a struggle, wherein Christ, the Paschal victim, victorious over death, reconciles us to the Father. We hear the story of Mary Magdalene, who upon finding the empty tomb of the risen Christ, and finding the clothes which once covered his head and limbs, proclaims: “Christ my hope has arisen.”

The sequence is translated in The English Hymnal as follows:

Christians, to the Paschal Victim 
Offer your thankful praises!
A Lamb the sheep redeemeth:
Christ, who only is sinless, 
Reconcileth sinners to the Father;

Death and life have contended 
In that combat stupendous:
The Prince of Life, who died, 
reigns immortal. 

Speak Mary, declaring 
What thou sawest wayfaring:

“The Tomb of Christ, who is living. 
The glory of Jesu’s Resurrection;
Bright angels attesting, 
The shroud and napkin resting. 
Yea, Christ my hope is arisen:
To Galilee he goes before you.”

Happy they who hear the witness, 
Mary’s word believing 
Above the tales of Jewry deceiving. 

Christ indeed from death is risen, 
our new life obtaining. 
Have mercy, victor King, ever reigning!
 
Here is a link to a classic rendering of the sequence by the Benedictine monks of Abbaye Notre-Dame de Triors: 
https://www.youtube.com/watch?v=vQ8zVV9G310

In his 1955 encyclical Musicae Sacrae, Pope Pius XII wrote: “It is the duty of all those to whom Christ the Lord has entrusted the task of guarding and dispensing the Church’s riches to preserve this precious treasure of Gregorian chant diligently and to impart it generously to the Christian people. … In the performance of the sacred liturgical rites this same Gregorian chant should be most widely used and great care should be taken that it be performed properly, worthily, and reverently.”

Amen to that.
 
By Fr Tomas
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Image: Christ resurrected on the day of judgement. Etching after M. de Vos [between 1590 and 1599?] Credit: Wellcome Collection. Attribution 4.0 International (CC BY 4.0)