On p.44 of the pastoral book you say that the Deut 24:1 “groundless divorce for ‘men-only’ did not become available until about the time of Jesus’ birth.” From what I read in Archer (219), it seems that men had this right for some time. She wrote:
In the first century the Shammaites attempted to restrict the man's power of divorce to charges of adultery, but such was the strength of the ancient view that the normally more progressive school of Hillel came out in opposition and declared that:[He may divorce her] even if she spoiled a dish for him, for it is written, 'Because he has found in her indecency in ANYTHING' (Deut. 24.1) (Gitt. 9.10). and R. Akiba (fl. c. 110-135 CE) lent his authority to the argument by adding: Even if he found another fairer than her, for it is written, 'And it shall be if she finds no favour in his eyes , , , ' (Deut. 24.1) (ibid.).It is apparent from Philo (Spec. Leg. 3.30), Josephus (Ant. 4.253), and other writers of our period that the reality was that of Akiba and the Hillelites. Society in the main would not brook a diminishment of the husband's power, and the general feeling, simply expressed by Ben Sira, was: If she go not as thou wouldst have her Cut her off from thy flesh (25.26).
So did you mean “groundless divorce for ‘men-only’” where they did not have to pay divorce money in a Hillelite court? Hence your other comments about why first century men would want to be sure which court they picked when they wanted to divorce (your “Jesus’ Old Testament Basis for Monogamy” 91).
Reply: Ben Sira certainly shows that groundless divorce existed before the Hillelites, and the Elephantine documents suggest it went back to at least the 5th C - for both men and women. What changed with the Hillelites was that it gained credence as a biblical ground for divorce because they found a way to derive it from Dt.24.1. By basing it in this verse, it became available for only men, because the case law in Dt.24.1-4 concerns a man who divorces his wife. Therefore they ask "Is it lawful for a MAN to divorce his WIFE for 'Any Cause'. Actually, they prob didn't say "for 'Any Cause'" - I think this was added by Matt. It would have been superfluous because the question was 'in the air' like "is it lawful to detain suspected terrorists" - anyone in the USA at present would mentally add "... indefinitely without charge", because of course it is lawful to detain someone suspected of a crime.
The Hillelites do not claim that this exegesis originated with Hillel (who was around perhaps the mid 1st C BCE) and they are debating it with Shammaites (who disappeared at 70CE) so the time period is the first half of the 1st C. Josephus and Philo already regard it as a fixed idea, though their Greek version of 'Any Cause' is different from each other and from Mark, so there was no standard translation. The rabbinic debate was already over and dead by 70CE because no-one appears to be bothered to use the term 'Any Cause' after 70 - it was just 'divorce' - ie it was already the only form of divorce in use in Judaism. By the 3rd C, the rabbis had forgotten so much that they misunderstood what the Shammaite slogan meant.
So, all in all, I'd say this arose very early in the 1st C.