IMPROPERS. – This is the name given to a series of lamentations that the Lord utters against the people judged for their ingratitude toward the benefits He has bestowed. The concepts expressed therein are undoubtedly of scriptural inspiration, but the text seems to derive from the apocryphal Esdras 13-24. They are sung on Good Friday during the Adoration of the Cross, to which they were added along with the Byzantine Trisagion.
The Greek Menologion places their origin during the reign of Theodosius, suggested by a boy during an earthquake; he would have invited the people to sing: «Sanctus Deus, Sanctus fortis, Sanctus et immortalis, miserere nobis», to which was later added: «Qui crucifixus es pro nobis miserere nobis», a formula very dear to the Monophysites, since it could be misunderstood as denying the sufficiently affirmed Trinitarian meaning that Jesus had been crucified only according to His humanity. Gregory VII, eighty-two years later, definitively omitted the scandalous interpretations from the Orientals (Letter to Simondo; I. VIII, ep. I; PL 137, 492). The given origin, however, is legendary. The oldest version of the I. is found in the Pontificale of Prudentius of Troyes (d. 861). The texts were collected with their variants by E. Martène (De antiquis Ecclesiae ritibus, IV, Antwerp 1764, col. 129 ff.; G. M. Tommasi, Opera, ed. A. Vezzosi, V, Rome 1752, p. 86; R. J. Heskett for Benevento [Paleografia musicale, 14 (1934)]). Today it is admitted that the I. were composed in the 6th century and came to the West from the Church of Jerusalem. In 12 propositions, the benefits of God are recalled: after the first three follows the Trisagion in Greek, then the «Popule Meus»; after the final repetition of the refrain, the antiphons for the Adoration of the Cross follow.