Catholic Encyclopedia - Septuagint Version

The importance of the Septuagint Version is shown by the following considerations: The Septuagint is the most ancient translation of the Old Testament and consequently is invaluable to critics for understanding and correcting the Hebrew text (Massorah), the latter, such as it has come down to us, being the text established by the Massoretes in the sixth century A.D. Many textual corruptions, additions, omissions, or transpositions must have crept into the Hebrew text between the third and second centuries B.C. and the sixth and seventh centuries of our era; the manuscripts therefore which the Seventy had at their disposal, may in places have been better than theMassoretic manuscripts.