The exilarch Bostanai married a Persian princess; after his death his other sons claimed her and her children as slaves

Bostanai was the first exilarch, the hereditary head of Babylonian Jewry, under Arab rule. The exilarchs claimed descent from King David. Jewish sources say the conquering caliph gave him a captive daughter of the Persian king Khosrow II as a wife. Hai Gaon names the caliph as Umar; Abraham ibn Daud says the princess was a daughter of Yazdegerd III and the caliph was Ali. She bore him sons. When Bostanai died, his sons by his Jewish wives said the princess was still a slave, and so were her children, and that they belonged to them as part of the estate. The Encyclopaedia Judaica says the claim rested on her never having converted to Judaism. The Jewish Encyclopedia says the judges split, then ruled that the Jewish sons must give letters of manumission to the princess and her son, on the presumption that Bostanai had freed her before marrying her. The question did not end. A Geniza fragment from Palestine calls all Bostanai's descendants children of a slave. The 10th-century gaon Sherira stressed that he descended from David but not from Bostanai. The first exilarchs after Bostanai came from his Jewish wife's son. A fourth-generation descendant of the Persian line, Zakkai, later held the office. Benjamin of Tudela was shown Bostanai's grave near Pumbedita in the 12th century.