Joel ben Isaac of Bonn

Not much is known about the life of Joel ben Isaac ha-Levi of Bonn, a leading talmudist. Joel, probably born in Mainz, belonged to a distinguished family, and his descendants were prominent German rabbis for at least five generations. Joel studied with the leading figures of Germany, including Ephraim of Regensburg (1110–1175), whom he debated in writing, often at great length. Joel’s son, Eliezer (1140–1225), wrote The Book of Ravyah (Sefer Ravyah), a halakhic compendium that frequently cited Joel’s rulings and responsa. Other works composed in Eliezer’s generation also quoted Joel’s writings. Joel also wrote piyyutim commemorating Jewish suffering during the Second Crusade.