Ira justa Conditoris. [Passiontide.] In the Office of the Most precious Blood of our Lord Jesus Christ this is the hymn at Matins.
This Office is one of those added to the Roman Breviary since 1735. In the Bologna edition, 1827, it is given in the Appendix to the Pars Vernalis as one of the festivals of March, and as a double of the first class; but by a decree of Pope Pius IX., Aug. 10, 1849, it is ranked as a double of the second class and appointed for the 1st Sunday in July.
The text is found as above in the Appendix, 1827, p. 233, in 6 stanzas, and is repeated in subsequent editions of the Roman Breviar. Also in Daniel, ii. p. 355. [Rev. James Mearns, M.A.]
Translation in common use:--
He Who once in righteous vengeance. By E. Caswall. Published in his Lyra Catholica, 1849, p. 85, in 6 stanzas of 6 lines; and again in his Hymns & Poems, 1873, p. 47. In 1853, stanzas i., iv.-vi. were given in the Cooke & Denton Hymnal, No. 6. This arrangement of the text has been repeated in a large number of hymn-books in Great Britain and America, and is the popular form of the hymn. In the 1862 Appendix to the H. Noted, No. 298, the full text is given; and in the Hymnary, 1872, stanza iii. is omitted.
--John Julian, Dictionary of Hymnology (1907)