An ancient hymn of the eastern church. “Holy God, Holy and Mighty, Holy Immortal One, Have mercy upon us” (BCP, p. 356). The term is from the Greek, meaning “thrice holy.” It is mentioned in the acts of the Council of Chalcedon (451). This hymn was used at the opening of the eucharistic rite in the east and in Gallican liturgies. It came to be used in the Roman rite as part of the reproaches on Good Friday. A paraphrase of the Trisagion was used in the anthem “In the midst of life,” which was included in the Burial Office of the 1549 BCP and all subsequent Prayer Books (see BCP, pp. 484-485, 492). This anthem is also used on Holy Saturday, after the gospel (and homily) (p. 283). The Hymnal 1982 Accompaniment Edition, Vol. 1, provides musical settings for this anthem (S 379, S 382). The 1979 BCP is the first Prayer Book to use the Trisagion as an alternative for the Kyrie at the opening of the eucharistic rite (p. 356). The Kyrie or Trisagion are normally used at the opening of the rite in Advent and Lent, when the Gloria in excelsis is not used. They may be used on other occasions. The Trisagion may be sung or said three times, or antiphonally (BCP, p. 406). Musical settings for the Trisagion are provided by The Hymnal 1982 (S 99-S 102), and the Accompaniment Edition, Vol. 1 (S 360). The Trisagion is also used at the beginning of the Reconciliation of a Penitent, Form Two (BCP, p. 449). The BOS recommends use of the Trisagion in the Way of the Cross as the procession goes from station to station. The Trisagion may also be used to conclude each station in the Way of the Cross.
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from “An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians,” Don S. Armentrout and Robert Boak Slocum, editors.