JOSEPH BAR ḤIYYA (ninth century), av bet din, gaon, later av bet din again, and once more gaon of Pumbedita (828–833) during one of the most crucial periods in the history of Pumbedita and the relationship between the academies of Pumbedita and Sura and the exilarchate. In the controversy between the exilarch David b. Judah and his brother Daniel, Joseph b. Ḥiyya and Abraham b. Sherira presided jointly over the academy until peace was restored, when Joseph b. Ḥiyya volunteered to renounce the office, temporarily resuming the position of av bet din. The two academies were then enabled to assert their full independence: according to the decree by the caliph al-Muʾmīn the exilarch was henceforth forced to submit to the judicial authority of the two academies.
B.M. Lewin (ed.), Iggeret Rav Sherira Ga'on (1921), 112; Abramson, Merkazim, 11.