For my own bookmark:
“No two Septuagint codices contain the same apocrypha, and no uniform Septuagint ‘Bible’ was ever the subject of discussion in the patristic church. In view of these facts the Septuagint codices appear to have been originally intended more as service books than as a defined and normative canon of Scripture,” E. E. Ellis, The Old Testament in Early Christianity (Baker 1992), 34-35.
“As we have seen, manuscripts of anything like the capacity of Codex Alexandrinus were not used in the first centuries of the Christian era, and since, in the second century AD, the Jews seem largely to have discarded the Septuagint…there can be no real doubt that the comprehensive codices of the Septuagint, which start appearing in the fourth century AD, are all of Christian origin,” R. Beckwith, The Old Testament Canon of the New Testament Church (Eerdmans 1986), 382.
“Nor is there agreement between the codices which of the Apocrypha t include. Codex Vaticanus, Codex Sinaiticus and Codex Alexandrinus all include Tobit, Judith, Wisdom and Ecclesiasticus, and integrate them into the body of the Old Testament, rather than appending them at the end; but Codex Vaticanus, unlike the other two, totally excludes the Books of Maccabees. Moreover, all three codices, according to Kenyon, were produced in Egypt, yet the contemporary Christian lists of the biblical books drawn up in Egypt by Athanasius and (very likely) pseudo-Athanasius are much more critical, excluding all apocryphal books from the canon, and putting them in a separate appendix. It seems, therefore, that the codices, with their less strict approach, do not reflect a definite canon so much as variable reading-habits; and the reading-habits would in the nature of the case be those of fourth and fifth-century Christians, which might not agree with those of first-century Jews,” ibid. 383.
“At this point we encounter the Greek Old Testament in the three great codices of the fourth and fifth centuries: Vaticanus, Sinaiticus and Alexandrinus…All exceeded the scope of the Hebrew Bible…In Vaticanus, however, all four of the books of Maccabees are missing and in Sinaiticus, 2 and 3 Macabees, as well as 1 Ezra, Baruch and Letter of Jeremiah—presumably only the result of lacunae in the text. Codex Alexandrinus, approximately one century younger, is, in contrast, much more extensive; it includes the LXX as we know it in Rahlfs’ edition, with all four books of Maccabees and the fourteen Odes appended to Psalms. The Odes also include the Prayer of Manasseh, previously attested only in the Syria Didaskalia and the Apostolic Constitutions,” M. Hengel, The Septuagint as Christian Scripture (Baker 2004), 57-58.
“It should be considered, further, that the Odes (sometimes varied in number), attested from the fifth century in all Greek Psalm manuscripts, contain three New Testament ‘psalms’: the Magnificat, the Benedictus, the Nunc Dimittis from Luke’s birth narrative, and the conclusion of the hymn that begins with the ‘Gloria in Excelsis.’ This underlines the fact that the LXX, although, itself consisting of a collection of Jewish documents, wishes to be a Christian book. The relative openness of the Old Treatment portion of these oldest codices also corresponds to that of its ‘New Testament’: Sinaiticus contains Barnabas and Hermas, Alexandrinus 1 and 2 Clement,” ibid. 59.