history, medicine, mathematics, astronomy, and other scientific topics; he was reputed to be one who knew all the "seven sciences". Biographers state that he never married or fathered children. He died at Kairouan, Tunisia, in 932. This date is given by most Arabic authorities who give his date of birth as 832. But Abraham ben Hasdai, quoting the biographer Sanah ibn Sa'id al-Kurtubi ("Orient, Lit." iv., col. 230), says that Isaac Israeli died in 942. Heinrich Grätz (Geschichte v. 236), while stating that Isaac Israeli lived more than one hundred years, gives the dates 845-940; and Steinschneider ("Hebr. Uebers." pp. 388, 755) places his death in 950. He died in Kairouan. Influence In 956 his pupil Dunash Ibn Tamim wrote an extensive commentary on Sefer Yetzirah, a mystical work of cosmogony which attributes great importance to the letters of the Hebrew alphabet and their combinations in determining the structure of the universe. In this work he cites Israeli so extensively that a few nineteenth-century scholars misidentified the commentary as Israeli's. Israeli's medical treatises were studied for several centuries both in the original Arabic and in Latin translation. In the eleventh century, Constantine Africanus, a professor at the prestigious Salerno school of medicine, translated some of Israeli's works into Latin. Many medieval Arabic biographical chronicles of physicians list him and his works. Israeli's philosophical works exercised a considerable influence on Christian and Jewish thinkers, and a lesser degree of influence among Muslim intellectuals. In the twelfth century, a group of scholars in Toledo transmitted many Arabic works of science and philosophy into Latin. One of the translators, Gerard of Cremona, rendered Israeli's Book of Definitions (Liber de Definicionibus/Definitionibus) and Book on the Elements (Liber Elementorum) into Latin. Israeli's work was quoted and paraphrased by a number of Christian thinkers including Gundissalinus, Albertus Magnus, Thomas Aquinas, Vincent de Beauvais, Bonaventura, Roger Bacon and Nicholas of Cusa. Isaac Israeli's philosophical influence on Muslim authors is slight at best. The only known quotation of Israeli's philosophy in a Muslim work occurs in Ghayat al-Hakim, a book on magic, produced in eleventh-century Spain, translated into Latin and widely circulated in the West under the title Picatrix. Although there are passages which correspond directly to Israeli's writings, the author does not cite him by name. His influence also extended to Moses Ibn Ezra (c. 1060-1139) who quotes Isaac Israeli without attribution in his treatise The Book