Sefer ha-Kabbalah ספר הקבלה

Abraham ibn Daud wrote it in Toledo around 4921—and wrote it with a clear aim. The Karaites said: the Oral Torah is an invention of the sages, there is no succession. Ibn Daud answered not with argument but with a list: here are the names, the generations, who learned from whom—from Moshe to the heads of the academies of his own century. The argument is that the list does not break.

From it too comes the tale of the four captives: four sages seized at sea and ransomed in different communities of the Mediterranean, each founding an academy where he landed. So, by that account, the learning passed from Babylonia to North Africa and Spain. Historians hold the tale to be composed rather than recorded: it explains where Spain's right to teach came from—and explains it a little too neatly. Yet it was that tale that made the Spanish academies the heirs of Sura and Pumbedita in the eyes of the whole dispersion.

For this reference work the book is a standing source: names and the order of generations in many articles come from it. So its limit must be said here as well. Ibn Daud wrote not a chronicle but a case, and where the case and exactness parted, he chose the case. Where his information differs from the Epistle of Rav Sherira, we hold to Sherira: he wrote closer in time, and answered a question about years, not about who was right.