Auctor beate saeculi

This Latin hymn of unknown authorship and date is appointed for the Feast of the Sacred Heart of Jesus. In editions of the Roman Breviary following 1735, it serves as the hymn at second Vespers when the feast is observed on its proper day (the Friday following the octave of Corpus Christi), or at both Vespers when transferred or ranked as a double of the first or second class. In English Catholic and monastic usage, it was appointed for Vespers on the Sunday or Friday after the Corpus Christi octave.

The full text is published in Hermann Adalbert Daniel's Thesaurus Hymnologicus (vol. iv, p. 311). In English common use, the hymn is primarily known through Edward Caswall's translation, "Jesu, Creator of the world," first published in his Lyra Catholica (1849) in six stanzas of four lines. An adaptation by Benjamin Hall Kennedy, "O Thou, by Whom the worlds were framed" (1863), was later altered to "Thou blest Redeemer of the world" in the Sarum Hymnal (1868).