We turn now to the third text that Robinson treats in Chapter X of Redating the New Testament, namely the Didache. Generally speaking, the Didache is one of the more difficult early Christian texts to work with, as our only Greek copy wasn't found until 1873, dates from the 11th century, and appears to be incomplete (incidentally, this copy is part of the Codex Hierosolymitanus, which also contains our only complete Greek copy of 1 Clement). Still, there is a general consensus that the Didache dates to the first century or so after Jesus's life. There is probably a general tendency to place it around 100, give or take a decade or two in either direction, and not surprisingly Robinson argues that this is on the high side. He instead argues that the Didache, more or less as we find it in the Codex Hierosolymitanus, was completed by c. 60.
The word "completed" is crucial here, as virtually all scholars agree that the text was composed over time, and might have originally constituted a multitude of disparate texts. Robinson agrees with this assessment, but notes correctly that "over time" is a relative term. He follows J.P. Audet, who argues in his 1958 work La Didachè: Instructions des apôtres (a classic work whose influence has been vitiated by the lack of an English translation) that the Didache was produced over a twenty-year period, spanning from 50 to 70. Robinson's only modification to Audet is to propose that the span was closer to 40 to 60. Why does Robinson place the Didache in this period? Numerous reasons. He suggests for instance that the ecclesiology of the Didache is most similar to that found in the authentic Pauline letters and paralleled in Acts: itinerant ministers, with a movement towards establishing permanent bodies of elders in the various communities. He suggests that the eschatology of the final chapter, 16 (which seems to breaks off, thus suggesting incompletion) finds its readiest parallels in 1 and 2 Thessalonians. In short, it seems to fit better with what we know about Christianity c. 50, give or take a decade, than the time around c. 100. He further suggests that the use of Synoptic materials looks it comes more from the period that the gospels were being formed than from the use of fully-formed gospels. Admittedly, these are all among the weaker arguments for establishing a text's date, but given the state of the data it might all that we can do. They do seem stronger than those used to defend the almost-entirely speculative hypothesis advanced in the late-19th century and still held by many today, namely that they represent an otherwise-unknown form of early-second-century Syrian (or, less commonly, Egyptian) Christianity.
One thing that I find interesting about this narrative is how well it coheres with another datum, namely the longer title of the Didache, which reads in English "The Teaching of the Lord to the Gentiles by the Twelve Apostles." It has long struck me as a remarkable coincidence that we have the Didache, the Epistle of James, the Gospel of Matthew, and the Gospel of Mark all being attributed to figures associated with the first-generation Jerusalem church and all evincing a close literary relationship. If there is no connection between this body of densely-related literature and Jerusalem than we have virtually to posit among the ancients an intentional effort to deceive on this point. It’s far from clear to me that such a conspiracy is better defensible on the data than the hypothesis that a religious movement that began in Judea happened to produce a considerable among of its earliest texts in Judea. And it also happens that, as best we can tell, during the 40s and the 50s the Jerusalem church expended considerable energy on thinking about the place of the Gentiles in the nascent movement. Given the state of the text-critical evidence we probably should not dismiss out of hand the possibility that the longer title provides data for considering the initial conditions under which the Didache was produced, and we should seriously entertain any hypothesis that can make good sense of the text overall as well as the title(s).