The Karaite disturbances also contributed to lessen the authority of the Exilarch. Until the time of Anan the academies and their colleges had been subordinate to the Prince of the Captivity, and to the principals of the schools chosen or confirmed by him; at the same time, however, they had no direct influence over the appointment to this office when it became vacant. But having once succeeded in dispossessing Anan of the Exilarchate, the Gaons determined that this power should not be wrested from their hands, and accordingly from this time exercised it on the ground that they could not allow princes of Karaite opinions to be at the head of the Jewish commonwealth. The Exilarchate, which had been hereditary since the time of Bostanaï, became elective after Anan, and the presidents of the academies directed the election. On the death of Chananya (Achunaï), and hardly ten years after Anan's defection from Rabbanism, a struggle for the Exilarchate broke out afresh between two pretenders, Zaccaï ben Achunaï and Natronaï ben Chabibaï. The latter was a member of the college under Judah. The two heads of the schools at this period, Malka bar Acha, of Pumbeditha (771-773), and Chaninaï Kahana ben Huna, of Sora (765-775), united to bring about the overthrow of Natronaï, and succeeded in procuring, through the Caliph's attendants, his banishment from Babylonia. He emigrated to Maghreb (Kairuan), in which city there had existed ever since its foundation a numerous Jewish population. Zaccaï was confirmed in the office of Exilarch. The Exilarchate continued to become more and more dependent on the Gaonate, which often deposed obnoxious princes, and not infrequently banished them. But as the Exilarchs, when they arrived at power, attempted to free themselves from this state of dependence, there occurred collisions which exerted an evil influence on the Babylonian commonwealth.