The Four Captives: the learning moves west

The account comes down in a single book: Abraham ibn Daud's Sefer ha-Kabbalah, written at Toledo around 4921.

Four sages left Babylonia to raise money for the academies. Their ship was seized by a commander of the caliph, and the captives were sold separately: one was ransomed at Alexandria, a second at Kairouan, a third—Rabbi Moshe ben Chanoch—at Cordoba; of the fourth Ibn Daud says he does not know where he went. And each, where he was redeemed, sat down to teach.

Of Cordoba the most is told. Rabbi Moshe came to the house of study in rags and no one knew who he was; he sat in a corner, and when the head of the academy stumbled over a law, he corrected him—and the community set him at its head that same hour. Hasdai ibn Shaprut, the caliph's court physician, rejoiced: now the Jews of Spain need not ask the law of the Geonim of Babylonia but could decide it themselves.

So it should be read. The account answers not "what happened" but "by what right". Historians see in it a tale of origins: it is too neat—four set out, four ransomed, four founded, each exactly where a community later flowered. Yet that learning did move from Babylonia to the West in these years is no legend but a fact; within a century and a half Sura and Pumbedita would close, and Cordoba, Kairouan and Fez would teach.