The real founder of the Uzbeg power was Abū-l-Khayr, a descendant of Shaybān in the sixth degree, who was born in A.H. 816 (1413). His rule extended over the western portion of the present Kirghiz steppes. About the year A.H. 870 (1465) a number of these Uzbegs, discontented with their Khān, Abū-l-Khayr, migrated into Moghūlistan, with the Sultans Girāy and Jānībeg, of the line of Jūjī.[428] Isan Bughā, the then Khān of Moghūlistan, or Jatah, received them hospitably, and allotted them some territories on the river Chū, to the west of his own domains. These emigrants were subsequently known as the Uzbeg-Kazāks, or simply Kazāks.[429] After the death of Abū-l-Khayr, in A.H. 874 (1469), a large number of his Uzbegs passed into Moghūlistan and joined their kinsmen.[430] Abū-l-Khayr overran Khwārazm and part of Turkestān; and at the beginning of the sixteenth century his son Mohammad Shaybānī, also known as Shāhī Beg, made himself master of Samarkand and Transoxiana, and was the first of the so-called dynasty of the Shaybānides. It is more than a mere coincidence that the appearance of the Uzbegs and Kazāks in Southern Central Asia was contemporaneous with Russia’s liberation from the Tartar yoke. Shaybānī Khān achieved the conquest of Transoxiana in A.H. 906 (1500),[431] but soon after this event Zahīr ud-Dīn Bāber, then aged nineteen, entered that country and captured Samarkand, Soghd, Miyānkul, Karshī, and other strong places; Bokhārā alone remaining in the possession of the Uzbegs. However, in the following year, A.H. 907 (1501), Shaybānī Khān defeated Bāber and regained the lost territory. By A.H. 911 (1505), from which date historians reckon the commencement of his reign,[432] he had made himself master of Transoxiana, Farghāna, Khwārazm, and Hisār.