Our timeline with respect to the emergence of the 'syntagma' (a term which means both 'writing' and 'constitution') for Christianity makes it seem almost certain that it was established in Latin. Hence the consistent 'list' which appears in our two earliest sources - the fragmentary citation from Hegesippus's Memoirs in Eusebius's Church History written in 147 CE and Justin Martyr's Dialogue with Trypho usually dated to the same year. This syntagma originally made reference to:
Marciani, Valentiniani, Basileidiani and Satorniliani
Beyond this we know very little with any certainty but this is nevertheless a significant starting point.
We can use the Byzantine chronographer Georgius Cedrenos as a witness to the fact that this syntagma was established during the reign of Hadrian. Even if we push the dating to the early years of Antoninus Pius the context is still the same - an official response to the 'instability' that occurred in Palestine. I don't see how this can be ignored any longer. Celsus is a clear witness to the fact that it was only recently that 'Judaism' and 'Christianity' were not only seen as separate traditions but more significantly that they should have a set constitution - the term 'constitution' being used here rather tentatively as meaning 'identity' as much as anything else. We are only beginning our investigation, but I would have to say that this is an important thing to have established. It helps explain why the Acts of the Apostles is best dated to this very same period. But more on that after the next break.