If Marcion was said to have written a systematic 'refutation' of Judaism - i.e. the 'Antitheses' - surely he had to have used a Greek translation of the Old Testament. The general attitude of scholars - foolishly - is that this 'rejection' was ultimately so 'childish' that it can be assumed to be haphazard. Of course this attitude is never spelled out as a rational argument. After all, it is a wholly irrational POV - the assumption that the Marcionites didn't have a preferred version of the Old Testament because they 'hated' it. Nevertheless the real truth is that scholars tend to shy away from things which clearly demonstrate (a) how little we know and (b) how silly all previous attempts to make sense of early Christianity are because they failed to acknowledge (a). To this end we have a clue as to what the Marcionite preference might have been.
In the fourhundred and twentieth footnote to Adolph von Harnack's History of Dogma, he notices a parallel between two second century translators of the Hebrew Bible into Greek:
According to Epiphanius, de mens. et pond. 14, 15, Aquila, the translator of the Bible, was first a Christian and then a Jew. This account is perhaps derived from Origen, and is probably reliable. Likewise according to Epiphanius (l. c. 17. 18), Theodotion was first a Marcionite and then a Jew.
While Harnack dismisses the possibility that a Marcionite could have been a Jew, this pre-Nazi German named 'Adolf' is ignoring the countless reports in the Church Fathers of Marcion's own Jewish sensibilities. The parallel between Theodotion and Aquila is particularly striking because (a) it comes from the same author and (b) it offers at least a suggestion to the unanswered question about which version of the Old Testament was employed by Marcionites.
Yet when we dig deeper it is uncertain whether Theodotion ever translated the entire Bible. Schaff in his entry for Theodotion notes "We learn from Jerome (in. Dan. iv. 6, p. 646) that Origen himself ("in nono Stromatum volumine") abandoned this supposed LXX Daniel for Theodotion's. Indeed, all the citations of Daniel, some of them long and important passages in Origen's extant works, agree almost verbatim with the text of Theodotion now current, and differ, sometimes materially, from that of the reputed LXX as derived from the Chistian MS. He seems, moreover, to have found the task of bringing its text to conform to the original by the aid of Theodotion's a hopeless one, as we may judge by his asterisks, obeli, and marginalia in the two MSS. referred to. Yet that this is the version which Origen placed as that of the LXX in the penultimate column of the Hexapla and Tetrapla is certain."
One wonders then whether 'Theodotion' is in fact properly identified as a translator of the entire Bible into Greek or rather merely a Marcionite who clung to a variant Greek text of Daniel. It is important also to note that in Suidas the entry for 'Theodotion' offers Theodotus as a variant. There was a well known 'Theodotus' at Rome during the time of Irenaeus - in fact there were two figures of the same name.
Irenaeus makes the following reference to Theodotion and his Old Testament at the end of the second century:
God, then, was made man, and the Lord did Himself save us, giving us the token of the Virgin. But not as some allege, among those now presuming to expound the Scripture, [thus:] Behold, a young woman shall conceive, and bring forth a son, Isaiah 7:14 as Theodotion the Ephesian has interpreted, and Aquila of Pontus, both Jewish proselytes. The Ebionites, following these, assert that He was begotten by Joseph; thus destroying, as far as in them lies, such a marvellous dispensation of God, and setting aside the testimony of the prophets which proceeded from God. For truly this prediction was uttered before the removal of the people to Babylon; that is, anterior to the supremacy acquired by the Medes and Persians. But it was interpreted into Greek by the Jews themselves, much before the period of our Lord's advent, that there might remain no suspicion that perchance the Jews, complying with our humour, did put this interpretation upon these words. They indeed, had they been cognizant of our future existence, and that we should use these proofs from the Scriptures, would themselves never have hesitated to burn their own Scriptures, which do declare that all other nations partake of [eternal] life, and show that they who boast themselves as being the house of Jacob and the people of Israel, are disinherited from the grace of God. [Against Heresies 3:21]
Of course it is typical just to go along with Irenaeus's suggestion that Theodotion 'must have been' an Ebionite. Yet this honor typically goes to Symmachus. Irenaeus does not say that Theodotion was a member of this sect, only that the Ebionites 'follow these" men (i.e. Aquila and Theodotion).
Almost all scholars now suppose that Theodotion was not in fact a translator per se but rather someone who 'corrected' or amended an existing translation. Perhaps he was Theodotus of Rome using and modifying an existing translation of various books of the Old Testament. He was however certainly identified as a Marcionite.
