About Yitzhak (Abu Sa'id) ibn Ezra (ibn Ezra ibn Shaprut)
Spanish poet of the twelfth century; son of Abraham ibn Ezra. He won fame as a poet at an early age, probably while still in his Spanish home. Al-Ḥarizi ("Taḥkemoni," iii.) says of him: "Like his father, Isaac also drew from the springs of poetry; and some of the father's brilliancy flashes in the songs of the son." He probably left Spain with his father, before 1140. In 1143 Isaac was in Bagdad as a protégé of the Arab Abu al-Barakat Hibat Allah (Nathanael). The poem in which he extols his patron and his commentary on Ecclesiastes has been preserved (ed. by Dukes in "Kokebe Yiẓḥaḳ," xxiv.; comp. Steinschneider, "Hebr. Bibl." i. 91). When Hibat Allah became converted to Islam, Isaac ibn Ezra followed his example. Al-Ḥarizi says (ib.): "But when he came into Eastern lands the glory of God no longer shone over him; he threw away the costly garments of Judaism, and put on strange ones." Abraham ibn Ezra mourned in two elegies over the apostasy of his son. One of these poems was composed three years after Isaac's abandonment of Judaism, as appears from the second strophe. Abraham ibn Ezra, therefore, could not have heard of the sad event until a long time afterward. Regarding the possible identity of Isaac ibn Ezra and an Isaac b. Abraham ha-Sefaradi, for whom a copy of the Hebrew translation of Ḥayyuj's works and of the Mustalḥiḳ was made by Abu al-Walid, see "R. E. J." xx. 140. : Grätz, Gesch. 3d ed., vi. 255; Steinschneider, Abraham ibn Ezra, p. 68; idem, Die Arabische Literatur der Juden, p. 184; Brody, Hebr. Bibl. iii. 124-126.
When Hibat Allah converted to Islam, Isaac ibn Ezra (Abu Hasdai Yitzhak ibn Ezra ibn Shaprut) converted too. Isaac ibn Ezra (son of Abraham ibn Ezra ibn Shaprut), had a son named Hasdai ben Isaac ibn ezra bn Shaprut (Abu Yusuf ben Yitzhak bin Ezra ibn Shaprut). Some Jewish scholars view Hasdai ibn Shaprut's father (the apostate previously known as Isaac bin Ezra) as the primary driver for enticing the heads of Jewish Academies, in Babylon, to come to Spain. The goal, as speculated among scholars, was to debase Jewish centers of learning, erode the power base of the Exilarchate, and help bring the fall of the Radhanite trade network; thereby shifting economic power plus intellectual and political authority to al-Andalus. Also, in 949, he became the right hand man (vizier) to the Muslim caliph of the Caliph of Cordoba.