Dating from the mid-380’s, not long before Codex Bezae’s paleographically-assigned date of ca 400, Ambrosiaster’s thinly-veiled attack on the Vulgate in his Commentary on Romans (chapter 5, verse 14) must be considered highly-relevant to the problem of Bezae’s origins as a bilingual codex, due especially to its concern with the interaction between the Greek and Latin traditions (see my working translation). Ambrosiaster criticizes the Vulgate for its dependence on divergent Greek texts whose pedigree cannot be verified, while at the same time, arguing for the genuineness of the Old Latin version whose reliability (he claims) can be verified with reference to the citations of ancient writers, such as Tertullian, Cyprian, and Victorinus (all three of whom are named explicitly).
Of course, Ambrosiaster could not have been unaware of discrepancies between Latin texts. His concern then must be on the latter point that a text is only as reliable as the authorities that certify its authenticity. Ambrosiaster apparently believes that he can distinguish between corrupted texts and the ancient text on the basis of their respective agreement with the citations of a select pool of authoritative writers. The implication here is that corrupt texts can be corrected on the basis of the appropriate selection of citations.
Now if Ambrosiaster’s method were applied to an actual document, the result would be a text with a series of quite deliberate parallels to the citations of a selection of old writers, embedded within a text that otherwise reflects the period of its production. Taken at face value, such a text might appear very ancient indeed, which is of course the intention. It might even appear as though the ancient writers cited in the text had themselves depended on this later text form.
While we know that stabilization of the Old Latin version was at the time a desideratum, the question is whether Ambrosiaster’s approach would ever have been sufficiently representative to have been applied in practice. But if such a scenario is plausible, the implications for Codex Bezae are momentous. When Bezae parallels a citation of Irenaeus, we can no longer be sure whether it is Irenaeus who used an early text form resembling Bezae’s text or whether Bezae’s producers considered Irenaeus a suitable authority for the correction of their text.
While we must remain ever aware of the limitations of our sources, the uncanny yet somewhat selective appearance in Bezae’s text of parallels with early writers appears at least consistent with Ambrosiaster’s criterion of authenticity (as it were), a connection that seems intriguing enough to pursue for potential insights into possible contexts for Bezae’s origins.