Trisagion (τρίς thrice, ἄγιος holy) is a doxology that is distinct from the sanctus concluding the Preface. The text of the Trisagion reads: "Hagios ho Theos, hagios ischyros, hagios athanatos, eleison hymas" [Holy God, holy and mighty, holy and immortal, have mercy on us]. The Trisagion was first mentioned in the 5th century as a devotional invocation that assumed a liturgical role in Eastern liturgies. For example, in the Byzantine Divine Liturgy of St. John Chrysostom, the Trisagion precedes the scriptural readings. From the East, it spread to the West, where it assumed a similar position in the eucharist of the ancient Gallican and Mozarabic rites. In the 11th century, the Trisagion appeared in the Roman rite for the liturgy of Good Friday, where it is sung alternately in Greek and Latin with the improperia or Reproaches during the veneration of the cross.
Bibliography: j. hanssens, Institutiones liturgicae de ritibus orientalibus, 3 v. (Rome 1932) 3:883–931. j. quasten, "Oriental Influence in the Gallican Liturgy," Traditio 1 (1943) 55–78. l. brou, "Etudes sur la liturgie mozarabe: le Trisagion de la messe d'après les sources manuscrites," Ephemerides liturgicae 61 (1947) 309–84. j. mateos, "Evolution historique de la liturgie de Saint Jean Chrysostome, II: Le chant du trisagion et la session à l’abside," Proche-Orient chrétien 17 (1967) 141–76. k. levy, "The Trisagion in Byzantium and the West," International Musicological Society: Congress Report 11 (Copenhagen 1972) 761–65. s.p. brock, "The Thrice-Holy Hymn in the Liturgy," Sobornost (incorporating Eastern Churches Review ) NS 7:2 (1985) 24–34.
[e. j. gratsch/eds.]