Rabbi Achai Gaon

Rabbi Achai Gaon lived in the 700s and wrote Sheiltos DeRabbi Achai. The book, arranged according to the weekly Torah portion, has each week's section divided into four parts. First, there is a general overview of laws based on that week's Parsha. Second, there is a question posed on halachic practice, the Sheilta related to the subject of the week. Third, there are moral lessons for the week. Fourth, there is a response to the Sheilta. For example, in the beginning of the volume, on Parshas Bereishis in connection to the Torah's mention of the Sabbath, Rabbi Achai discusses laws of honoring the Sabbath, quoting inspirational selections from the Talmud regarding the greatness of the day. The Sheilta ponders the question of whether someone fasting on Friday may continue his fast up to nightfall, even though he is entering the Sabbath in an unpleasant state. Rabbi Achai's response is that the fast is indeed completed until nightfall. According to tradition, Rabbi Achai wrote in such an easy, non-scholarly style because he had a son who was not interested in exerting himself in his studies, and the Rabbi believed that this book would help the son gain basic Torah knowledge.

Rabbi Amram Gaon

Living in the 800s, Rabbi Amram Gaon compiled the first official siddur, on which all subsequent prayer books are based. Responding to a request from a distant community,Rabbi Amram wrote a detailed siddur for the weekdays and all holidays, including the laws of prayer. Although various versions evolved, such as Nusach Sefard, Nusach Ashkenaz, and Nusach Ari, all follow the basic format laid down by Rabbi Amram.

Rabbi Saadiah Gaon

Born and raised in Egypt, and living in the 800-900s, Rabbi Saadiah Gaon was the only non-Babylonian to hold the post of Gaon throughout the hundreds of years of the Gaonim. While in his 20s, he became famous throughout the Jewish world when he wrote a book decisively refuting the Karaite movement. Utilizing a complete command of Hebrew and Scriptures to defeat the Karaites, Rabbi Saadiah directly caused the Karaites to lose much of their great appeal. Several years later, he settled the dispute over the calendar by conclusively proving that Rabbi Aharon ben Meir was incorrect. Realizing his unparalleled greatness, the Resh Galusa appointed the 36-year-old Saadiah as Gaon of the yeshiva of Sura.

However, this idyllic state of affairs did not last long. Rabbi Saadiah opposed the Resh Galusa's ruling on a complicated case, and when the two could not reach an agreement a great conflict erupted. Rabbi Saadiah excommunicated the Resh Galusa, and the Resh Galusa imposed a ban on Rabbi Saadiah. Eventually, Rabbi Saadiah had to flee from the Resh Galusa, going into hiding for seven years.

During that time, Rabbi Saadiah wrote many books, the most famous of which was Emunos VeDeos, the first work ever to organize the basic beliefs of Judaism in one place. Approaching Jewish belief from a rational viewpoint, Rabbi Saadiah wrote that because three million people witnessed G‑d’s giving the Torah at Mount Sinai, and then transmitted it to succeeding generations, it is a certainty that G‑d did indeed give the Jews the Torah at Mount Sinai. Eventually, Rabbi Saadiah and the Resh Galusa reconciled their differences, and Rabbi Saadiah was reinstated as Gaon. Nevertheless, the entire episode took a great toll on him. After five years, at the age of 50, Rabbi Saadiah passed away, and was greatly mourned by Jews everywhere. His epitaph could be one of his most famous sayings: "Our nation is a nation only because of the Torah."

Rabbi Sherira Gaon

In the 900s, together with his son, Rabbi Hai Gaon, Rabbi Sherira Gaon wrote great numbers of responsa, many of which have survived. His magnum opus, however, is the Iggeres DeRabbi Sherira Gaon, a detailed analysis of the transmission of the Oral Law and rabbinic authorities, traced for some 1,000 years, from the Tannaim to his own time. Virtually all extant knowledge of this time, particularly that of the Amoraim, Rabbanan Savoroi, and Gaonim, is based on this book. Rabbi Sherira lived to be 100, and died under mysterious circumstances. Differing opinions exist as to whether he was executed by the Babylonian king, died in prison, or passed away naturally.

Upon Rabbi Sherira's death in 1006, his son Rabbi Hai was installed as Gaon. The following Sabbath, several changes were made in the Torah and Haftarah readings. For example, the verse "Let

G‑d ...appoint a man over the congregation" (Numbers 27:16), referring to Joshua's succession of Moses, was added to the weekly Torah reading. The regular Haftarah was replaced by a passage dealing with the death of King David and his son Solomon’s accession to the throne. The last verse was changed from "And Solomon sat upon the throne of his father David, and his kingdom was firmly established,"

(I Kings 2:13) to "And Hai sat upon the throne of his father Sherira, and his kingdom was firmly established."

Rabbi Hai Gaon

Rabbi Hai Gaon, who died in 1038, was the last and greatest of all Gaonim. During his lifetime, Rabbi Hai attracted thousands of students from all over the Jewish world, from as far away as Europe. Unlike the earlier Gaonim, Rabbi Hai traveled to faraway Jewish communities, including Rome, spreading Torah learning on an unprecedented scale. So great was his teaching that many of Rabbi Hai’s disciples became the leaders of the succeeding generation. In terms of his scholarship, many of Rabbi Hai’s responsa and writings are extant, dealing to a great extent with rules of commerce, such as oaths, deposits, and terms of sale. In explaining numerous remarkable stories found throughout the Talmud, Rabbi Hai took a rational approach, writing that many of the tales are parables and allusions to various concepts, and are not to be taken literally. With Rabbi Hai Gaon's passing, the Gaonic Era came to a close, and Babylonia concomitantly lost its status as the Jewish people’s supreme Torah center.