Gershom ben Judah. – Rabbinic authority, known as “the light of the diaspora,” who lived at the end of the 10th and beginning of the 11th century and died at Mainz. Many young men from the most diverse countries flocked to the Talmudic school he directed. He was lenient in judging certain Jews of Mainz, including his own son, who had converted to Christianity in order to escape the imperial ban imposed by Emperor Henry II. To avoid uncertain textual variants, he himself transcribed the text of the *Gérmàr* (q.v.) and of the Bible, and composed a commentary on the Talmud in the style of the *gé'ônfîm* (q.v.). He was also a great decisor (q.V. DECISORS).
Among the “institutions of G.” (some of which date from later periods but were transmitted under his name) are to be counted: the prohibition of polygamy (though in Gershom’s mind this prohibition was temporary, Western Judaism declared it permanent), the prohibition of divorce against the will of the wife, the obligation of the community to support women abandoned by their husbands, the prohibition of seizing deposits (not constituting a true pledge) for unpaid debts, the prohibition of resorting (except in cases of great importance) to non-Jewish tribunals, and the obligation to observe epistolary secrecy. Gershom is the author of many liturgical compositions.