In the latter cases, when the respective kings corresponded, the letters were conveyed by special embassies. One might expect this epistolary activity to display itself at an even more developed stage in the records of Rabbinical times. But this is by no means the case, for the Rabbinical references to letters in the beginning of the common era are few and far between. Polemic epistles make their appearance; but they are the letters of non-Jewish missionaries like Paul. This form of polemical writing possessed many advantages; the letters were passed on from one reader to another; they would be read aloud, too, before gatherings of the people to whom they were addressed. Maimonides, in later times, frequently adopted this method of communicating with whole communities, and many of the Geonim and other Jewish authorities followed the same plan. But somehow the device seems not to have commended itself to the earliest Rabbis. Though we read of many personal visits paid by the respective authorities of Babylon and Palestine to one another, yet they appear to have corresponded very rarely in writing. The reason lay probably in the objection felt against committing the Halachic, or legal, decisions of the schools to writing, and there was little else of consequence to communicate after the failure of Bar-Cochba's revolt against the Roman rule. It must not be thought, however, that this prohibition had the effect we have described for very long. Rabbi Gamaliel, Rabbi Chananiah, and many others had frequent correspondence with far distant places, and as soon as the Mishnah acquired a fixed form, even though it was not immediately committed to writing, the recourse to letters became much more common. Pupils of the compilers of the Mishnah proceeded to Babylon to spread its influence, and they naturally maintained a correspondence with their chiefs in Palestine. Rab and Samuel in particular, among the Amoraim, were regular letter-writers, and Rabbi Jochanan replied to them. Towards the end of the third century this correspondence between Judea and Babylon became even more active. Abitur and Abin often wrote concerning legal decisions and the doings of the schools, and thereby the intellectual activity of Judaism maintained its solidarity despite the fact that the Jewish people was no longer united in one land. In the Talmud we frequently read, "they sent from there," viz. Palestine. Obviously these messages were sent in writing, though possibly the bearer of the message was often himself a scholar, who conveyed his report by word of mouth. Perhaps the growth of the Rabbi's practice of writing responses to questions--a practice that became so markedly popular in subsequent centuries--may be connected with the similar habit of the Roman jurists and the Christian Church fathers, and the form of response adopted by the eighth century Geonim is reminiscent of that of the Roman lawyers. The substance of the letters, however, is by no means the same;