His successor, Chosrau I., surnamed Anūshirawān “the Just,” stands forth as the most illustrious figure in the annals of ancient Persia. Chroniclers agree in depicting him as a wise and benevolent ruler, and one who made his prowess reflected in distant regions. His first care was to restore order in a realm which still groaned under the curse of Mazdakism; his next to crush the Ephthalites, whose incursions into his eastern provinces had been as disastrous as those of the Roman legions into Armenia. In the meanwhile the Ephthalites were being threatened from another quarter by the Turks. The Turks proper, that is the Tu-kiué of the Chinese, first appear in the history of the Sāsānides about A.D. 550. At that period the Turks were divided into two distinct khanates--(1) the Eastern Turks,[67] who possessed the vast territory between the Ural and Mongolia; and (2) the Western Turks, or Tu-kiué, who ruled in Central Asia from the Altai to the Jaxartes. About 550 the Khākān of the Turks, whose name was Tumen, being elated with successes he had gained over the Tartars,[68] made so bold as to demand in marriage the daughter of the Khākān of the Juen-Juen, Tiu-ping. On receiving an insulting refusal, Tumen at once declared war against the Juen-Juen; at the same time he married the daughter of the Chinese emperor, with whose aid he defeated Tiu-ping. Tumen then took the title of Il-khān (or khān of the people), and established his court in the mountain of Tu-kin, near the sources of the Irtish. He only enjoyed his newly acquired empire for a short time, for in the following year (A.D. 553) he died. His son Ko-lo mounted the throne, but died very shortly afterwards, and was succeeded by his illustrious brother Mokan-khān, whom we find in 554 entering into relations with Anūshirawān the Just. Though he had finally crushed the Juen-Juen, and became master of their vast country, he was fearful of the superiority of the Chinese, and therefore turned his arms in a westerly direction.[69] The Turks now crossed the Jaxartes and entered Badakhshān, where they encountered the Ephthalites, with whom, according to Tabari, they at first dwelt in peace.