Jerome first undertook a revision of the Psalter with the help of the Septuagint about the year 383, when living at Rome. This revision, which obtained the name of the Roman Psalter “probably because it was made for the use of the Roman Church at the request of Damasus,” was retained until the pontificate of Pius V. (a.d. 1566). Before long “the old error prevailed over the new correction,” the faults of the old version crept in again through the negligence of copyists; and at the request of Paula and Eustochium, Jerome commenced a new and more thorough revision. The exact date is not known; the work was in all probability done at Bethlehem in the years 387 and 388. This edition, which soon became popular, was introduced by Gregory of Tours into the services of the Church of France, and thus obtained the name of the Gallican Psalter. In 1566 it superseded the Roman in all churches except those of the Vatican, Milan, and St. Marks, Venice.
Long ago, when I was living at Rome, I revised the Psalter, and corrected it in a great measure, though but cursorily, in accordance with the Septuagint version. You now find it, Paula and Eustochium, again corrupted through the fault of copyists, and realise the fact that ancient error is more powerful than modern correction; and you therefore urge me, as it were, to cross-plough the land which has already been broken up, and, by means of the transverse furrows, to root out the thorns which are beginning to spring again; it is only right, you say, that rank and noxious growths should be cut down as often as they appear. And so I issue my customary admonition by way of preface both to you, for whom it happens that I am undertaking the labour, and to those persons who desire to have copies such as I describe. Pray see that what I have carefully revised be transcribed with similar painstaking care. Every reader can observe for himself where there is placed either a horizontal line or mark issuing from the centre, that is, either an obelus (†) or an asterisk (*). And wherever he sees the former, he is to understand that between this mark and the two stops (:) which I have introduced, the Septuagint translation contains superfluous matter. But where he sees the asterisk (*), an addition to the Hebrew books is indicated, which also goes as far as the two stops.