From the Epistle to the Galatians, number one in Marcion's canon, but number four in ours
However this is not a convincing enough argument to say for certain that the Marcionites had Galatians first in their canon.
Epiphanius also writes:
But I shall also go on to the next part, the texts from the Apostle which he still preserves, and which I have, again, selected in the same way. I have put the ones from the Epistle to the Galatians first, and keep that order throughout, for in Marcion's canon Galatians stands first. At the time I did not make my selection in his order but in the order of the Apostolic Canon, and put Romans first. But here I cite in accordance with Marcion's canon.
This is particularly interesting because Epiphanius introduces the subject of alleged 'editorial emendations' to the Pauline letters Romans first. Yet the passages cited by Epiphanius are basically identical with those of Tertullian's commentary. Interestingly both omit other notable alterations brought up in Origen's lost commentary on Galatians such as the omission of the reference to 'the Father' raising Jesus in Galatians 1:1.
It would stand to reason then to assume that Epiphanius and Tertullian are using the same source or at least separate versions of an older anti-Marcionite treatise that had a Galatians first ordering. This treatise becomes our common window into the Marcionite world. Undoubtedly these were two different versions of the same original treatise which undoubtedly passed through the hands of Irenaeus in the same way as the Philosophumena and Against Heresies use common material in different ways. However the Galatians first ordering was common to both source texts.
Tertullian never actually says that the Marcionite canon was Galatians first. Instead he talks about a text called or identified as an 'antitheses' at the head of a Marcionite codex which reinforces the separation of the Law and the gospel. This can't be Galatians because Galatians cannot be described as an 'antitheses.' But 1 Corinthians certainly can as we have recently demonstrated and at one point in Against Marcion Tertullian specifically references the ordering of the Marcionite canon as Corinthians first.
I think therefore that scholarship has wrongly assumed that the Marcionite canon began with Galatians. This develops as an unfortunate byproduct of (a) not examining our existing sources about the Marcionite canon critically and (b) mistaking the Galatians first feature of Against Marcion as a sign of the Marcionite canon rather than that of the original author of the source material who condemns the tradition. It is unlikely that Epiphanius even knew of the existence of 'Catholic' New Testament canons which placed Galatians first in their ordering. Schmid rightly brings them up in his Marcion und Sein Apostolos (1995). And many others have noted the Latin and Syriac evidence for this tradition.
Nevertheless Epiphanius's specific reference to the Marcionite Galatians first canon is one of many false inferences made by the fourth century bishop. He also claims for instance that the Marcionite Epistle to the Laodiceans is a separate epistle from the canonical to the Ephesians. This is not what Tertullian tells us. Instead the Latin Father rightly notes that 'to the Laodiceans' is the name of our 'to the Ephesians.' Neither Epiphanius nor Tertullian ever saw a Marcionite canon. They were both making all their inferences from a common literary text probably written or edited by Irenaeus of Lyons.
Oh and by the way. A 'Corinthians first' Apostolikon is not a theoretical abstraction. It is confirmed by the very early - Catholic - Muratorian canon ...
