Born in Toledo about 1089-1092. He traveled extensively: Rome 1140, Salerno 1141, Mantua 1145, Verona 1146, Lucca 1148, Beziers 1156, London, 1158, Narbonne 1160. He died in 1167, probably at Calahorra. Hispano-Jewish philosopher, astrologer, translator from Arabic into Hebrew, and Hebrew grammarian. One of the greatest Biblical commentators of the Middle Ages, one of the forerunners of modern criticism, and much admired by Spinoza on that account. He was one of the first to translate writings of Muslims into Hebrew. He wrote various books on mathematics and astrology, on the calendar, and on the astrolabe; eight treatises on astrology were completed at Lucca in 1148. One of his main titles to fame is that through his wanderings in Provence, France, and England, he helped to propagate among the Jews of Christian Europe (who, unlike their Spanish brethren, did not know Arabic) the rationalistic and scientific points of view which had been developed in Spain by Muslims and Jews on the basis of Greco- Muslim knowledge.

He translated from Arabic into Hebrew three treatises on grammar by Judah Hayyuj (second half of the tenth century), Rome 1140; two treatises on astrology by Mashallah, before 1148; al-Biruni's commentary on al-Khwarizmi's tables, Narbonne 1160. The last mentioned is known only through Ibn Ezra's version.

Ibn Ezra's mind was a strange mixture of rationalism and mysticism. His writings show his deep interest in magic squares and the mystical properties of numbers. He explained a decimal system of numeration: the first nine letters of the Hebrew alphabet, plus a circle for the zero, with place value. Problems involving the product of complex fractions.