TheAcharonim follow theRishonim, the "first ones"—the rabbinic scholars between the 11th and the 16th century following theGeonim and preceding theShulchan Aruch. The publication of theShulchan Aruch thus marks the transition from the era of Rishonim to that of Acharonim.
The distinction between theAcharonim,Rishonim andGeonim is meaningful historically. According to the widely held view inOrthodox Judaism, the Acharonim generally cannot dispute the rulings of rabbis of previous eras unless they find support from other rabbis in previous eras. Yet the opposite view exists as well: InThe Principles of Jewish Law Orthodox RabbiMenachem Elon wrote:
[such a view] "inherently violates the precept ofHilkheta Ke-Vatra'ei, that is, the law is according to the later scholars. This rule dates from the Geonic period. It laid down that until the time of Rabbis Abbaye and Rava (4th century) the Halakha was to be decided according to the views of the earlier scholars, but from that time onward, the halakhic opinions of post-talmudic scholars would prevail over the contrary opinions of a previous generation. See Piskei Ha'Rosh, Bava Metzia 3:10, 4:21, Shabbat 23:1
Hilkheta Ke-Vatra'ei can be interpreted such that the Orthodox view does not constitute a contradiction, with an appeal to understand it within the greater context of Torah. While authority may go to the scholars of a later generationwithin a particular era, the Talmud does not allow scholars of a later era to argue with scholars of anearlier era without support from other scholars of an earlier era.
This is displayed in "hundreds of instances" in the Talmud in which Amora’im are challenged by Tanna’itic sources with the term מיתיבי and the Amorai'm unable to "deflect the challenge". An Amora called Rav is challenged by Tannai’tic sources "and is vindicated by the statement,Rav tanna hu upalig"- "Rav is a Tanna and disagrees (inEiruvin 50b,Kesubos 8a, and elsewhere). A similar case exists for Rav Chiya, a borderline Tanna inBava Metzia 5a. This clearly implies that the only reason they are able to get away with disagreeing is because they are Tannaim. There are "only a handful of possible exceptions [to the rule] that theAmora’im did not, in fact argue with theTanna’im."[1]
The question of which prior rulings can and cannot be disputed has led to attempts to precisely define which rulings are within the Acharonim era. According to many rabbis the Shulkhan Arukh is from an Acharon. Some hold that RabbiYosef Karo'sBeit Yosef has the halakhic status of a work of a Rishon, while his laterShulkhan Arukh has the status of a work of an Acharon.[2]
Note: This list is incomplete and is only intended to provide a small selection from the broad list of prominent rabbinic figures of the Acharonic era. For a more comprehensive list, seeList of rabbis.