QAṢR IBN HUBAYRAH (Kasr ibn Hubayrah), town that was situated south of the ruins of ancient Babylon, west of the Euphrates (i.e., then its eastern arm, which was known as the Sura River). Qaẓr ibn Hubayrah was founded by Omar ibn Hubayrah, the last governor of Babylonia appointed by the *Ummayyad caliphs; the town bears his name. A report by the Arab geographer al-Muqaddasī, dating from the end of the tenth century, states that Qaṣr ibn Hubayrah had a large Jewish community. According to *Nathan ha-Bavli, it was the original home of *David b. Zakkai, the *exilarch who had a bitter controversy with R. *Saadiah Gaon. At the beginning of the 12th century, when the town of *Ḥilla was founded and became a transit point for the district's caravans and its trade center, Qaṣr ibn Hubayrah lost its importance and eventually fell into a state of ruin.
G. Le Strange, The Lands of the Eastern Caliphate (1930), 70f., 83.