Semikhah lapses: the ordained courts of the Land of Israel cease to function

What exactly lapsed. Not learning and not judging, but a particular legal category. Ordination—"they ordain him by name, they call him Rabbi" (Sanhedrin 13b)—was performed by three, at least one of them himself ordained, and conferred three things unavailable otherwise: authority to judge cases of fines (and through them corporal and capital jurisdiction), eligibility for the Sanhedrin, and authority to fix the months and intercalate the years by sighting the moon. The rabbi of the post-talmudic centuries is a scholar and a judge, but not a samukh.

Why it could not travel with the people. "There is no ordination outside the Land" (Sanhedrin 14a); Maimonides (Hil. Sanhedrin 4:6) adds that neither the ordainers' own ordination nor their presence in the Land helps if the ordinand is outside it. Across the third to fifth centuries the centre of gravity of Jewish learning moves to Babylonia—and ordination cannot follow it. That is why the Babylonian masters are called Rav and not Rabbi, and why semikhah breaks earlier than the chain of reception of the Torah, and in a different register: it never applied to the Babylonian amoraim at all.

The evidence is cumulative and gives no date. First, the titles. Second, the calendar: by Hil. Kiddush ha-Chodesh 5:1 the months may be sanctified by sighting only by the Sanhedrin of the Land of Israel or by an ordained court with its authority, "but at a time when there is no Sanhedrin in the Land of Israel, months are not fixed and years are not intercalated save by this reckoning by which we reckon today." So the shift from sighting to calculation is the best-dated symptom that ordained courts no longer exist. Third, the suppression of the Patriarchate after Gamaliel VI, c. 425 CE under Theodosius II, and the Roman legislation of the late fourth century restricting ordination and assembly.

On Hillel II and 359—why that date must not be printed bare. The tradition attributes the fixed calendar to the patriarch Hillel II in 4119 AM (358/359 CE). It has one source: a responsum of Rabbi Hai Gaon dated 4752 AM (992), preserved in Abraham bar Hiyya's Sefer ha-Ibbur—that is, a report six centuries later. The Talmud does not know the name "Hillel II"; the Yerushalmi associates the calendar rules with Rabbi Yose; and the fixed calendar was not in force as a single completed system in 359—as Sacha Stern showed (Calendar and Community, Oxford 2001), and as J. J. Ajdler concedes from the traditional side, accepting 358/359 as an inception date while stating plainly that "the name of Hillel II is not mentioned in the Talmud and it is not certain at all that he had a direct part in this calendar."

What this event does not mean. It does not mean that the transmission of the Torah broke: Maimonides' enumeration ends two generations later, at Ravina and Rav Ashi, and for a different, sociological reason which he names himself—"Israel was scattered through all the lands with an exceeding scattering… but individuals gather." Semikhah and the chain of reception are two different things, and they break at different times and for different reasons. Nor does it mean that restoration is impossible: Maimonides (Hil. Sanhedrin 4:11) holds that if all the sages of the Land of Israel agreed, the ordination would be valid—and closes with the words "and the matter requires decision," which the popular accounts omit. The attempt of 5298 AM at Safed has its own entry here.

And on what is not here. The story of Rabbi Yehudah ben Bava, who ordained five men between Usha and Shefaram at the risk of death, is told as the end of semikhah. The error is nearly universal: the story stands more than two centuries earlier, in the Hadrianic persecution of c. 3895–3898 AM, and it says the opposite—how ordination was preserved at the cost of a life. The five ordained there—Rabbi Meir, Rabbi Yehudah, Rabbi Shimon, Rabbi Yose and Rabbi Elazar ben Shamua—are the tannaim on whom the Mishnah largely rests.