Geonim (Hebrew: גאונים; also transliterated Gaonim) were the presidents of the two great rabbinical colleges of Sura and Pumbedita, in Babylonia, and were the generally accepted spiritual leaders of the Jewish community world wide in the early medieval era, in contrast to the Resh Galuta (Exilarch) who wielded secular authority over the Jews in Islamic lands.
Geonim is the plural of גאון (Gaon’), which means "pride" or "splendour" in Biblical Hebrew and since the 1800s "genius" as in modern Hebrew. As a title of a Babylonian college president it meant something like "His Excellency."
The Geonim played a prominent and decisive role in the transmission and teaching of Torah and Jewish law. They taught Talmud and decided on issues on which no ruling had been rendered during the period of the Talmud.
The period of the Geonim began in 589 (Hebrew date: 4349), after the period of the Sevora’im, and ended in 1038 (Hebrew date: 4798). The first gaon of Sura, according to Sherira Gaon, was Mar Rab Mar, who assumed office in 609. The last gaon of Sura was Samuel ben Ḥofni, who died in 1034; the last gaon of Pumbedita was Hezekiah Gaon, who was tortured to death in 1040; hence the activity of the Geonim covers a period of nearly 450 years.
There were two major Geonic academies, one in Sura and the other in Pumbedita. The Sura academy was originally dominant, but its authority waned towards the end of the Geonic period and the Pumbedita Gaonate gained ascendancy (Louis Ginzberg in Geonica).
 Role in Jewish life
The Geonim officiated, in the last place, as directors of the academies, continuing as such the educational activity of the Amoraim and Saboraim. For while the Amoraim, through their interpretation of the Mishnah, gave rise to the Talmud, and while the Saboraim definitively edited it, the Geonim’s task was to interpret it; for them it became the subject of study and instruction, and they gave religio-legal decisions in agreement with its teachings.
During the geonic period the Babylonian schools were the chief centers of Jewish learning; the Geonim, the heads of these schools, were recognized as the highest authorities in Jewish law. Despite the difficulties which hampered the irregular communications of the period, Jews who lived even in most distant countries sent their inquiries concerning religion and law to these officials in Babylonia.
In the latter centuries of the geonic period, from the middle of the tenth to the middle of the eleventh, their supremacy lessened, as the study of the Talmud received care in other lands. The inhabitants of these regions gradually began to submit their questions to the heads of the schools in their own countries. Eventually they virtually ceased sending their questions to Babylonian Geonim.
 The title "Gaon"
The title of gaon came to be applied to the heads of the two Babylonian academies of Sura and Pumbedita, though it did not displace the original title of Rosh Yeshivah Ge’on Ya’akov (Hebrew, head of the academy, pride of Jacob). The Aramaic term used was Resh metivta.
The title gaon properly designated the office of head of the academy. The title became popular in use around the end of the sixth century. As the academies of Sura and Pumbedita were invested with judicial authority, the gaon officiated as supreme judge.
The organization of the Babylonian academies recalled the ancient Sanhedrin. In many responsa of the Geonim, members of the schools are mentioned who belonged to the "great sanhedrin," and others who belonged to the "small sanhedrin." In front of the presiding gaon and facing him were seated seventy members of the academy in seven rows of ten persons each, each person in the seat assigned to him, and the whole forming, with the gaon, the so-called "great sanhedrin." Gaon Amram calls them in a responsum ("Responsa der Geonim," ed. Lyck, No. 65) the "ordained scholars who take the place of the great sanhedrin." (A regular ordination ("semichah") is of course not implied here: that did not exist in Babylonia, only a solemn nomination taking place.)
Gaon Ẓemaḥ refers in a responsum to "the ancient scholars of the first row, who take the place of the great sanhedrin." The seven masters, or "allufim" and the "ḥaberim," the three most prominent among the other members of the college, sat in the first of the seven rows. Nine sanhedrists were subordinated to each of the seven allufim, who probably supervised the instruction given during the entire year by their subordinates. The members of the academy who were not ordained sat behind the seven rows of sanhedrists.
 Works of the Geonim
Early in the Geonic era, the majority of the questions asked them were sent from Babylonia and the neighboring lands. Jewish communities in these regions had religious leaders who were somewhat acquainted with the Talmud, and who could on occasion visit the Jewish academies in Babylon. A literature of questions and answers developed, known as the responsa literature.
The questions were usually limited to one or more specific cases, while the responsum to such a query gave a ruling, a concise reason for it, together with supporting citations from the Talmud, and often a refutation of any possible objection.
More discursive were the responsa of the later geonim after the first half of the ninth century, when questions began to be sent from more distant regions, where the inhabitants were less familiar with the Talmud, and were less able to visit the Babylonian academies, then the only seats of Talmudic learning.
The later geonim did not restrict themselves to the Mishnah and Talmud, but used the decisions and responsa of their predecessors, whose sayings and traditions were generally regarded as authoritative. These responsa of the later geonim were often essays on Talmudic themes, and since a single letter often answered many questions, it frequently became book-length in size. Two important examples of such books are the Siddur of Amram Gaon, addressed to the Jews of Spain in response to a question about the laws of prayer, and the Epistle of Sherira Gaon, which sets out the history of the Mishnah and the Talmud in response to a question from Tunisia.
Some of the responsa that have survived are in their original form, while others are extant only as quotations in later works. Many have been found in the Cairo Genizah.
Examples of responsa collections are:
- Halakhot Pesukot min ha-Geonim (Brief Rulings of the Geonim): Constantinople 1516
- Sheelot u-Teshuvot me-ha-Geonim: Constantinople 1575
- Shaare Tzedek (Gates of Justice), edited by Nissim ben Hayyim: Salonica 1792, containing 533 responsa arranged according to subject and an index by the editor
- Teshuvot Ha-Geonim, ed. Mussafia: Lyck 1864
- Teshuvot ha-Geonim: Shaare Teshuvah with commentary Iyye ha-Yam by Israel Moses Hazan: Livorno 1869; linked here
- Shaare Teshuvah ha-Shalem, ed. Leiter: New York 1946
- Teshuvot Geone Mizrach u-Ma’arav, ed. Mueller: Berlin 1888
- Lewin, B. M., Otzar ha-Geonim: Thesaurus of the Gaonic Responsa and Commentaries Following the Order of the Talmudic Tractates (13 vols): Haifa 1928
- Assaf, Simhah, Teshuvot ha-Geonim: Jerusalem 1927 (second volume 1942).
 Other works
Individual Geonim often composed treatises and commentaries. Three handbooks on Jewish law are:
- Halachot Pesukot of Yehudai Gaon (not to be confused with the responsa collection of the same name): this was the basis of many other abridgments
- She’iltot of Achai Gaon
- Halachot Gedolot, by Simeon Kayyara.
 The Kallah
During the first three weeks of the kallah month the scholars seated in the first row reported on the Talmud treatise assigned for study during the preceding months; in the fourth week the other scholars and also some of the pupils were called upon. Discussions followed, and difficult passages were laid before the gaon, who also took a prominent part in the debates, and freely reproved any member of the college who was not up to the standard of scholarship. At the end of the kallah month the gaon designated the Talmudic treatise which the members of the assembly were obliged to study in the months intervening till the next kallah should begin. The students who were not given seats were exempt from this task, being free to choose a subject for study according to their needs.
During the kallah, the gaon laid before the assembly a number of the questions that had been sent in during the year from all parts of the Diaspora. The requisite answers were discussed, and were finally recorded by the secretary of the academy according to the directions of the gaon. At the end of the kallah month the questions, together with the answers, were read to the assembly, and the answers were signed by the gaon. A large number of the geonic responsa originated in this way; but many of them were written by the respective geonim without consulting the kallah assemblies convened in the spring.
 Individual geonim
Chananel Ben Chushiel (Rabbeinu Chananel) and Nissim Gaon of Kairouan, though not holders of the office of Gaon, are often ranked among the Geonim. Others, perhaps more logically, consider them as constituting the first generation of Rishonim. Maimonides sometimes uses the term "Geonim" in an extended sense, to mean "leading authorities", regardless of what country they lived in.
Rishonim (Hebrew: ראשונים; sing. ראשון, Rishon, "the first ones,") were the leading Rabbis and Poskim who lived approximately during the 11th to 15th centuries, in the era before the writing of the Shulkhan Arukh and following the Geonim. Rabbinic scholars subsequent to the Shulkhan Arukh are known as " Acharonim — the latter ones".
The distinction between Rishonim and Geonim is meaningful historically; in Halakha (Jewish Law) the distinction is less important. According to a widely held view in Orthodox Judaism, Acharonim generally cannot dispute the rulings of rabbis of previous eras unless they find support of other rabbis in previous eras. On the other hand, this view is not formally a part of halakhah itself, and according to some rabbis is a violation of the halakhic system. In the The Principles of Jewish Law Orthodox rabbi Menachem Elon writes that such a view:
- inherently violates the precept of Hilkheta 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
 Some Rishonim
- Abba Mari, (Minhat Kenaot), 13th century Provençal rabbi.
- Don Isaac Abravanel, (Abarbanel), 15th century philosopher and Torah commentator
- Israel Bruna, (Mahari Bruna), 15th century German Rabbi and Posek
- Abraham ibn Daud, (Sefer HaKabbalah), 12th century Spanish philosopher
- Abraham ibn Ezra, (Even Ezra), 12th century Spanish-North African Biblical commentator
- David Abudirham, said to be a student of the Baal Ha-Turim (but this is doubtful)
- Samuel ben Jacob Jam’a, 12th century North African rabbi and scholar
- Asher ben Jehiel, (Rosh), 13th century German-Spanish Talmudist
- David Kimhi, (RaDaK) 12th century French biblical commentator, philosopher, and grammarian
- Yaakov ben Moshe Levi Moelin, (Maharil), 14th century codifier of German minhag
- Obadiah ben Abraham of Bertinoro, (Bartenura), 15th century commentator on the Mishnah
- Bahya ibn Paquda, (Hovot ha-Levavot), 11th century Spanish philosopher and moralist
- Hasdai Crescas, (Or Hashem), 14th century Talmudist and philosopher
- Dunash ben Labrat, 10th century grammarian and poet
- Rabbenu Gershom, 11th century German Talmudist and legalist
- Gersonides, Levi ben Gershom, (Ralbag), 14th century French Talmudist and philosopher
- Eliezer ben Nathan, 12th century poet and pietist
- Hillel ben Eliakim, (Rabbeinu Hillel), 12th century Talmudist and disciple of Rashi
- Ibn Tibbon, a family of 12th and 13th century Spanish and French scholars, translators, and leaders
- Isaac Alfasi, (the Rif), 12th century North African and Spanish Talmudist and Halakhist; author of "Sefer Ha-halachoth".
- Jacob ben Asher, (Baal ha-Turim ; Arbaah Turim), 14th century German-Spanish Halakhist
- Joseph Albo, (Sefer Ikkarim), 15th century Spain
- Joseph ibn Migash 12th century Spanish Talmudist and rosh yeshiva; teacher of Maimon, father of Maimonides
- Meir Abulafia, (Yad Ramah), 13th century Spanish Talmudist
- Maimonides, Moshe Ben Maimon, (Rambam), 13th century Spanish-North African Talmudist, philosopher, and law codifier
- Mordecai ben Hillel, (The Mordechai), 13th century German Halakhist
- Nahmanides, Moshe ben Nahman, (Ramban), 13th century Spanish and Holy Land mystic and Talmudist
- Nissim Ben Jacob (Rav Nissim Gaon), 10th century Tunisian Talmudist
- Nissim of Gerona, (RaN), 14th century Halakhist and Talmudist
- Rashi, (Solomon ben Yitzchak), 11th century Talmudist, the primary commentator of Talmud
- Elazar Rokeach, (Sefer HaRokeach), 12th century German rabbinic scholar
- Samuel ben Judah ibn Tibbon, 12th-13th century French Maimonidean philosopher and translator
- Tosafists, (Tosafot), 11th, 12th and 13th century Talmudic scholars in France and Germany
- Yehuda Halevi, (Kuzari), 12th century Spanish philosopher and poet devoted to Zion
- Menachem Meiri, (Meiri), 13th century Talmudist
- Yom Tov Asevilli, (Ritva), 13th century Talmudist
- Yitzhak Saggi Nehor, (Isaac the Blind), 12th-13th century Provencal Kabbalist
- Solomon ben Aderet, (Rashba), 13th century Talmudist
- Aharon HaLevi, (Ra’ah), 13th century Talmudist
- Zerachiah ha-Levi of Girona, (Baal Ha-Maor) 12th century Talmudist
- Meshullam ben Jacob, (Rabbeinu Meshullam Hagodol), 12th century Talmudist
Acharonim (Hebrew: אחרונים; sing. אחרון, Acharon; lit. "last ones") is a term used in Jewish law and history, to signify the leading rabbis and poskim (Jewish legal decisors) living from roughly the 16th century to the present.
The Acharonim follow the Rishonim, the "first ones" – the rabbinic scholars between the 11th and the 16th century following the Geonim and preceding the Shulkhan Arukh. The publication of the Shulkhan Arukh thus marks the transition from the era of Rishonim to that of Acharonim.
According to Orthodox Jewish tradition, scholars in one era within the history of halachic development do not challenge the rulings of previous-era scholars, and hence Acharonim cannot dispute the rulings of rabbis of previous eras unless they find support from other rabbis of previous eras.
The question of which prior rulings can and cannot be disputed has led to efforts to define which rulings are within the Acharonim era with precision. According to many rabbis the Shulkhan Arukh is from an Acharon. Some hold that Rabbi Yosef Karo’s Beit Yosef has the halakhic status of a work of a Rishon, while his later Shulkhan Arukh has the status of a work of an Acharon.
- ^ See Kesef Mishna (Maamrim 2:2), Kovetz Igros Chazon Ish (2:26)
 Some Acharonim
menachem mendel scneerson, 20th century leader of jewery in america
- Isaac Abendana, 17th century Sephardic scholar in England
- Jacob Abendana, 17th century Sephardic rabbi in England
- Isaac Aboab da Fonseca, 17th century Dutch scholar and Kabbalist, first Rabbi in the Americas
- Yehudah Leib Alter (Sfas Emes), Gerrer rebbe.
- Bezalel Ashkenazi (Shitah Mekubetzet), 16th century Talmudist
- Chaim Joseph David Azulai (Chida), 18th century scholar and traveler, pioneered history of rabbinic writings
- Yair Bacharach (Havvot Yair), 17th century German Talmudist
- Naftali Zvi Yehuda Berlin (Netziv, HaEmek Davar), 19th century head of Volozhin Yeshiva in Lithuania
- Josef Chaim of Baghdad (Ben Ish Chai), 19th century Iraqi Halakhist, Posek, Kabbalist and communal leader
- Moses ben Jacob Cordovero (Ramak), 16th century Holy Land Kabbalistic scholar
- Eliyahu Eliezer Dessler (Michtav Me’Eliyahu), 20th century religious philosopher and ethicist
- Dovber of Mezeritch (Maggid), 18th century Eastern European mystic, primary disciple of the Baal Shem Tov
- Samuel Eidels (Maharsha), 16th century Talmudist famous for his commentary on the Talmud
- Elijah ben Solomon (Gra, Vilna Gaon), 18th century Lithuanian Talmudist and Kabbalist, leader of the Mitnagdim (opponents of Hasidic Judaism)
- Mordechai Eliyahu, Halakhist, Posek, and former Sephardic Chief Rabbi of Israel
- Jacob Emden, 18th century Danish/German scholar
- Baruch Epstein (Torah Temimah), 20th century Lithuanian Torah commentator
- Moshe Mordechai Epstein (Levush Mordechai), 20th century Talmudist and co-head of Slabodka Yeshiva
- Yechiel Michel Epstein (Aruch ha-Shulchan), 19th/20th century Halakhist and Posek
- Jonathan Eybeschutz, 18th century scholar, Dayan of Prague, accused of heresy
- Moshe Feinstein (Igrot Moshe), 20th century Russian-American Halakhist, Posek, and Talmudist
- Nosson Tzvi Finkel (Alter/Sabba of Slabodka), early 20th century founder of Slabodka Yeshiva, Lithuania. Disciples opened major yeshivas in US and Israel
- Kalonymus Haberkasten, 16th century Polish rabbi, Rosh Yeshiva of many early Acharonim
- Hillel ben Naphtali Zevi (Bet Hillel), 17th century Lithuanian scholar
- Samson Raphael Hirsch, 19th century German rabbi, founder of the Torah im Derech Eretz movement
- Yitzchok Hutner (Pachad Yitzchok), 20th century European-born, American and Israeli Rosh Yeshiva
- Moshe Isserles (Rema), 16th century Polish halakhic authority and Posek, author of HaMapah component of the Shulkhan Arukh.
- Avrohom Yeshaya Karelitz (Chazon Ish), 20th century Belarussian-born, leading halakhic authority and leader of Haredi Judaism in Israel.
- Yisrael Meir Kagan (Chofetz Chaim), 20th century Polish Halakhist, Posek, and moralist
- Yosef Karo (the Mechaber), 16th century Spanish and Land of Israel legal codifier of the Shulkhan Arukh code of Torah Law
- Abraham Isaac Kook, 20th century philosopher and mystic, first chief rabbi of Palestine
- Judah Loew ben Bezalel (Maharal), 16th century Prague mystic and Talmudist
- Isaac Luria (Ari), 16th century Cairo and Holy Land mystic, founder of Lurianic Kabbalah
- Solomon Luria (Maharshal), 16th century Posek and Talmudist
- Moshe Chaim Luzzatto (Ramchal), 18th century Italian philosopher, mystic, and moralist
- Meir Leib ben Yechiel Michel (Malbim), 19th century Russian preacher and scholar
- Meir Simcha of Dvinsk (Ohr Sameiach, Meshech Chochmah), Lithuanian-Latvian Talmudist and communal leader
- Menasseh Ben Israel, 17th century Portuguese/Dutch Kabbalist, diplomat and publisher
- Obadiah ben Abraham of Bertinoro, (Bartenura), 15th century commentator on the Mishnah
- Avraham Aharon Price of Toronto, Canada, 20th century scholar, writer, educator, and community leader.
- Chaim Rabinowitz, Rosh Yeshivah in Telz, Lithuania
- Yisrael Lipkin Salanter, 19th century Lithuanian ethicist and moralist
- David HaLevi Segal (Taz), 16th century Halakhist, major commentator on the Shulkhan Aruch
- Sforno, 15th, 16th, and 17th-century family of Italian Torah scholars and philosophers
- Obadiah ben Jacob Sforno (Sforno), 16th century Italian scholar and rationalist
- Shalom Sharabi, 18th/19th-century Yemenite Sage, Kabbalist and founder of the Beit El Yeshiva, Jerusalem
- Moses Sofer (Chatam Sofer), 19th century Slovakian rabbi
- Chaim HaLevi Soloveitchik ("Reb Chaim Brisker"), 19th century Rosh Yeshivah in Volozhyn
- Chaim Vital, 16th century Kabbalist and primary disciple of Rabbi Isaac Luria
- Ovadia Yosef, Iraqi-born Halakhist, Posek and Sephardic Chief Rabbi of Israel
- Yisroel ben Eliezer (Baal Shem Tov) considered to be the founder of Hasidic Judaism
- David ben Solomon ibn Abi Zimra (Radbaz), 15th/16th century Halakhist, Posek and Chief Rabbi of Egypt
- Moshe Zevulun Margolies ("RaMaZ")