The Archdiocese of Boston is reviving an ancient Holy Week devotion called Tenebrae, a prayer service during which candles and lights are gradually extinguished to symbolize the death of Jesus Christ on the cross. The Office of Tenebrae, which originated around the seventh or eighth centuries, A.D., will be held April 7 at the Cathedral of the Holy Cross at 7:30 p.m.

According to Msgr. Frederick J. Murphy, rector of the cathedral, Tenebrae, which means “darkness” in Latin, has not been celebrated at the cathedral for over 50 years. He said that Archbishop Seán P. O’Malley asked that the service be reinstated.

Tenebrae “was usually done in the seminaries, but is has passed out of use” in the archdiocese for reasons he is unaware of, said Msgr. Murphy. Msgr. Murphy explained that the Vatican requests dioceses to pray the Office of Tenebrae during Holy Week.

The Church’s 1988 “Circular Letter Concerning the Preparation and Celebration of the Easter Feasts,” says that Tenebrae has a “special place in the devotion of the faithful as they [meditate] upon the Passion, death and burial of the Lord while awaiting the announcement of the Resurrection.”

The hour-long service April 7 will include the chanting of psalms, lamentations, canticles, choral responsories and a homily. Generally, the service begins with the nave of the cathedral or church in darkness except for 15 lit candles in the “Tenebrae hearse,” a triangular candlestick, at the front of the altar.

During the service one of the 15 will be extinguished after each psalm until only one candle remains lit. The lights inside the cathedral will also be gradually dimmed as each candle is extinguished. The one remaining candle represents Christ’s promise to conquer death and darkness. The final candle is then extinguished representing the “temporary triumph of the prince of darkness over the Light of the World,” said the archdiocese.

A loud noise is heard at the conclusion of the service to represent the shaking of the earth that occurred after Christ’s death, after which the congregation leaves the cathedral in silence.