KHOREZM (Ar. Khwarizm ), formerly also called Khīva, district in N.W. Uzbekistan, on the lower course of the Amu Darya River (Oxus), S. of the Aral Sea. From references in the Chronicles of the Arab historian al-Ṭabarī (838–923) to the Arab conquest of Khorezm, and from related passages in the Cambridge Document (see *Khazars), S.P. Tolstov concluded that the religion of the people of Khorezm before the Arab conquest was a peculiar syncretistic form of Judaism and that this was imported to Khazaria by survivors from the Judaizing circles from Khorezm (i.e., around 712 c.e.). The refugees were responsible not only for the Khazar conversion to Judaism but also, through setting aside the original Khazar khāqān and making their chief, *Būlān, the real ruler of Khazaria, responsible for the establishment of the Khazar dual kingship. However, no firm evidence exists for these conclusions and some of Tolstov's details are manifestly incorrect: e.g., that R. Isaac Sangari, traditionally credited with playing an important part in the Khazars' conversion to Judaism, should be identified with Khāmjird (presumed = Khangiri, a name found on some Khorezmian coins), who is mentioned by al-Ṭabarī. Yet in al-Ṭabarī's account Khāmjird is evidently the name of a region and not of a person. Tolstov further held that at one time, apparently in the eighth century, Khazaria and Khorezm formed a single state. However, his evidence, based largely on coins, is again far from conclusive. Similarly doubtful is his projected second union between Khazaria and Khorezm in the 10th and 11th centuries.
Nevertheless it is clear that some relations existed between Khorezm and Khazaria. Caravans passed between the two countries, and a corps of some thousands of men who had originally come "from the neighborhood of Khwārizm" were stationed at the Khazar capital, *Atil, in the tenth century (according to the contemporary Arab historian, al-Masʿūdī).
M. ibn J. al-Ṭabarī, Annales: Tarīkh al-Rusul wal-Mulūk … ed. by M.J. de Goeje, ser. 1 pt. 5 (repr., 1964), 2903; ser. 2 pt. 2 (repr., 1964), 1142–43, 1236–41; cf. Fr. tr. by M.H. Zotenberg, 3 (1871), 573; 4 (1874), 177; Abu-Raiḥān al-Bīrūnī, The Chronology of Ancient Nations, tr. and ed. by c.e. Sachau (1879), 42; D.M. Dunlop, History of the Jewish Khazars (1954), index s.v.Khwārism; A.N. Poliak, Kazariyyah (1951), index; Baron, Social2, 3 (1954), 326; S. Szyszman, in: rhr, 152 (1957), 186–90; S.P. Tolstov, Po sledam drevnekharezmiyskoy tsivilizatsii (1948: Auf den Spuren der altchoresmischen Kultur, 1953), esp. chs. 9–10; idem, in: Sovetskaya etnografiya (1946), 94–104; M.I. Artamonov, Istoriya Khazar (1962), 283–7 and index; F. Altheim and R. Stiehl, in: Anales de historia antigua y medieval, 8 (1955), 56–61; idem, Finanzgeschichte der Spaetantike (1957), 264–72.