The liturgical year is a great and ongoing proclamation by the Church of the Gospel of Jesus Christ and a celebration of the mystery of the word.
Through this yearly cycle, the Catechism of the Catholic Church explains, "the various aspects of the one paschal mystery unfold" (No. 1171). The Easter triduum holds a special place in the liturgical year because it marks the culmination of the yearly celebration in proclaiming the passion and resurrection of Jesus Christ.
The Latin word triduum refers to a period of three days and has long been used to describe various three-day observances that prepared for a feast day through liturgy, prayer and fasting. But it is most often used to describe the three days before the great feast of Easter: Holy Thursday, Good Friday and Holy Saturday and the Easter Vigil. The General Norms for the Liturgical Year state that the Easter triduum begins with the evening Mass of the Lord's Supper on Holy Thursday, "reaches its high point in the Easter Vigil, and closes with evening prayer on Easter Sunday" (No. 19).
Just as Sunday is the high point of the week, Easter is the high point of the year. The meaning of the great feast is revealed and anticipated throughout the triduum, which brings the people of God into contact -- through liturgy, symbol and sacrament -- with the central events of the life of Christ: his last supper, his trial and crucifixion, his time in the tomb and his resurrection from the dead.
In this way, "the mystery of the resurrection, in which Christ crushed death, permeates with its powerful energy our old time, until all is subjected to him" (CCC, No. 1169). During these three days of contemplation and anticipation the liturgies emphasize the sacrificial death of Christ on the cross, and the sacraments of baptism and the Eucharist, by which the faithful enter into the life-giving passion of Christ and grow in hope of eternal life in him.