d. c. 1134

Known only through his surviving works, he translated a number of important mathematical and astronomical texts from Arabic and Hebrew to Latin. He worked with other translators, especially Savasorda (Abraham bar Hiyya ha-Nasi). His versions of Ptolemy and other Greek writers proved very popular, and many copies of his translations still survive across Europe. His work helped introduce many new areas to European mathematics, such as the solutions to quadratic equations, and advanced trigonometry.