“Holy God, Holy Mighty, Holy Immortal . . . have mercy upon us.” The Trisagion was introduced into the Byzantine liturgy by Proclus of Cyzicus, who succeeded Nestorius as Bishop of Constantinople (431-446 a.d.). However, a papyrus from the fourth century preserved in the collection of the University of Strasbourg includes a Trisagion in the Liturgy of St. Mark.
In the Coptic tradition, there is an insertion after the first phrase, “Holy God, Holy Mighty, Holy Immortal,” and before the final phrase, “Have mercy upon us.” In the first stanza, the insertion is “Who was born of a Virgin”; in the second stanza it is “Who was crucified for us”; and in the third stanza it is “Who rose from the dead and ascended into the heavens.”
The phrase “Who was crucified for us” was introduced by the Patriarch of Antioch, Peter the Fuller (470, 485-489 a.d.). It became a slogan for those opposed to the Council of Chalcedon (i.e., Miaphysites). The interpretation of this hymn was meant to proclaim, by using an expression from the Nicene Creed, an essential aspect of Cyrillian theology. The Word as the only “subject” in Christ is also the subject of the death “in the flesh,” which is “His own.” Undoubtedly the Trisagion was interpreted as a hymn to the incarnate Word, and the interpolated form of it was formally orthodox.
It would have been decidedly heretical had it been addressed to the Trinity, implying the passion of the three persons or the divine essence. The great theologian Severus of Antioch in his homily on the Annunciation, pronounced between 512 and 513 a.d. (i.e., the same year or few months later), explained clearly the meaning of the Trisagion. He delivered his last cathedral homily in Antioch on the same subject in 518.
It is important to mention that the Coptic Church addresses this hymn to Christ. The first stanza, “Who was born of the Virgin,” and the last stanza, “Who rose from the dead and ascended into the Heavens,” are accepted by Chalcedonians and anti-Chalcedonians alike. The Coptic Church is completely separate from the “heresy” of Theopaschiste.
This addition was the cause of many riots, such as that which took place in November 512 a.d. This event was narrated by the Chalcedonian John Malalas and the anti-Chalcedon Pseudo-Dionysius of Tel Mahre.