The opening words in Greek of an invocation, or doxology, or hymn-for it may properly receive any of these titles-which in the Roman Liturgy is sung during the Improperia, or "Reproaches" at the ceremony of the Adoration of the Cross, on Good Friday. The brief hymn is then sung by two choirs alternately in Greek and Latin, as follows: First Choir: Agios o Theos (O Holy God). Second Choir: Sanctus Deus. First Choir: Agios ischyros (Holy, Strong). Second Choir: Sanctus fortis. First Choir: Agios athanatos, eleison imas (Holy, Immortal, have mercy on us). Second Choir: Sanctus immortalis, miserere nobis. Thus the hymn appears in the Office of Holy Week, with the Greek words `Ágios ó theòs, `ágios ìskhurò, `Ágios àthánatos èléeson èmâs expressed in Latinized characters, chosen to represent the Greek pronunciation (e.g. eleison imas for eleéson émas, the aspirate, as in modern Greek, remaining unheard). The hymn is thus sung twelve times, alternating with a series of varied "Reproaches".

From the Latin word Sanctus thrice said, the hymn is sometimes referred to as Tersanctus, and is thus apt to be confused with the triple Sanctus at the end of the preface at Mass. In the rubrics of the Greek Liturgy, in which the hymn is said very frequently, it is always referred to as the Trisagion (trís thrice, `ágios = holy), and is thus generally and properly known. It is sung at the Lesser Entrance, or solemn processional carrying of the book of the Gospels at Mass, in the Constantinopolitan and Armenian liturgies and in that of St. Mark. In the Gallican Liturgy it was placed both before and after the Gospel. The hymn is certainly of great antiquity, and perhaps much older than the event assigned by the Greek Menology as its origin. The legend, which may be considered a highly improbable one, recounts that during the reign of the younger Theodosius (408-450), Constantinople was shaken by a violent earthquake, 24 September, and that whilst the people, the Emperor, and the Patriarch Proclus (434-446) were praying for heavenly succour, a child was suddenly lifted into midair, to whom forthwith all cried out Kyrie eleison; and that the child, returning again to earth, admonished the people with a loud voice to pray thus: "O Holy God, Holy and Strong, Holy and Immortal", and immediately expired. The fact that the hymn was one of the exclamations of the Fathers at the Council of Chalcedon (451), and that not only is it common to all the Greek Oriental liturgies, but was used also in the Gallican Liturgy [St. Germanus of Paris, (d. 576), referring to it as being sung both in Greek and in Latin: "Incipiente præsule ecclesia Ajus (that is, Agios) psallit, dicens latinum cum græco", as also previously in Greek alone, before the Prophetia] suggests from such a widespread and apparently common use the conclusion that the hymn is extremely ancient, perhaps of apostolic origin. Benedict XIV thought that the Greek formula was joined with the Latin in allusion to the divine voice heard at Constantinople. But the explanation seems hardly necessary, in view of the retention of Kyrie eleison in the Roman Liturgy, as well as of such Hebrew words as Amen, Alleluia, Hosanna, Sabaoth. Reverence for antiquity, and the influence of liturgy upon liturgy, would suffice to explain the Greek form. It is true that the Kyrie eleison is not joined to a Latin version. On the other hand, it is so simple and occurs so frequently, that its meaning could easily be learned and remembered; whereas the Trisagion, elaborate and rarely used, might well receive a parallel version into Latin. Various additions made to it from time to time in the East have either disfigured its simplicity or endangered its orthodoxy. Thus, the phrase "Who wast crucified for us", added to it by Peter the Fuller, in order to spread the heresy of the Theopaschites (who asserted that the Divine Nature suffered upon the cross), while susceptible of a correct interpretation, was inserted nevertheless with heretical intent. Traditionally, the hymn had always been addressed to the Holy Trinity (Isaias, vi, 3). Subsequently, Calandion, Bishop of Antioch, sought both to allay the tumults aroused by the addition and to remove its evil suggestion by prefixing to it the words "Christ, King", thus making it refer directly and unequivocally to the Incarnate Word: "O Holy God, Holy and Strong, Holy and Immortal, Christ, King, Who wast crucified for us, have mercy on us." His wellmeant effort did not succeed, and his emendation was rejected. Subsequently, the heretic Severus, Patriarch of Antioch, wrote to prove the correct ascription of the hymn to the Son of God, and made the use of the addition general in his diocese.

Gregory VII (1073-85f) wrote to the Armenians, who still used the new formula, bidding them avoid all occasion of scandal and suspicion of wrong interpretation, by cancelling a formula which neither the Roman nor any Eastern Church, save the Armenian, had adopted. The injunction seems to have been disregarded; for when, centuries after, union with the Armenians was again discussed, a question was addressed (30 January, 1635) to Propaganda, whether the Armenians might still use the formula "Who suffered for us", and was answered negatively. Variations of the traditional formula and Trinitarian ascription are found in the ArmenoGregorian rite. These are addressed to the Redeemer, and vary with the feast or office. Thus, the formula of Peter is used on all Fridays; on all Sundays: "Thou that didst arise from the dead"; on Holy Thursday: "Thou that wast betrayed for us"; on Holy Saturday: "Thou that wast buried for us"; on the Feast of the Assumption: "Thou that didst come to the death of the Holy Mother and Virgin", etc. The ArmenoRoman rite has suppressed all of these variations. The Trisagion is sung in the Greek Church at all the canonical hours and several times during the long Massservice. In the Latin church it is sung only on Good Friday, as we have seen. Sung throughout the impressive ceremony of the Adoration of the Cross, the polyphonic musical setting of Palestrina for both the "Reproaches" and the Trisagion, assuredly a masterpiece, perhaps the masterpiece of that prince of church song, adds an overpowering pathos of music to the words, and constitutes, like the Hallelujah Chorus of Handel, a marvel of simplicity achieving a marvellous effect.

H.T. HENRY