Beginning with the Mass of the Lord's Supper on the evening of Holy Thursday, and concluding with evening prayer of Easter Sunday night, these three days form the high point, or culmination, of the liturgical year for Catholics through the celebration of the passion and resurrection of Christ.

This single celebration spanning three days, which includes the solemnity of Easter, takes precedence over all other observances in the church calendar. In 2005, those observances would include St. Gabriel (March 24), the archangel who announced to Mary she would be the mother of God (parish: San Gabriel Mission, San Gabriel), and Annunciation (transferred this year from March 25 to April 4), observing the event itself (parish: Annunciation, Arcadia).

March 24: Holy Thursday/Mass of the Lord's Supper. This Mass (and in some dioceses, the Chrism Mass) is the only Mass permitted on this day. We commemorate the Lord's Supper, and Christ's example of washing the feet of his disciples, the mandatum, or mandate to love and serve one another. (Originally no Eucharist was celebrated the week before Easter. By the fourth century, the custom of Cena Domini, the Supper of the Lord, had spread.)

March 25: Good Friday. A continuation of the Triduum, the day includes the proclamation of the Passion, the veneration of the cross, and holy Communion. No Masses are celebrated on this day.

March 26: Holy Saturday/Easter Vigil. This "night of nights," when Christ rose from the dead, begins with the Service of Light, when a new fire is blessed and the Easter Candle is lighted. The liturgy traces our salvation history through the Liturgy of the Word. Adults are then baptized and confirmed, and join with the entire community for Liturgy of the Eucharist, as they receive the Body and Blood of Christ for the first time.