To the north and north-east of Kashmīr, the provinces of Baltistan and Ladakh are inhabited by a mixed Tibetan race, among whom Islam has been firmly established for several centuries, but the date and manner of its introduction is unknown. The Muhammadans of Baltistan tell of four brothers who came from Khurāsān and brought about a revival of the faith, but appear to have no tradition regarding the earliest propagandists. [952] Up to the middle of the nineteenth century Islam appeared to be making progress, but this tendency was counteracted by the encouragement which Maharaja Ranbir Singh gave to the followers of the Buddhist faith. In Ladakh there are a number of half-castes, called Arghons, [953] born of Tibetan mothers and Muhammadan fathers, traders who have come to Leh and persuaded the Tibetan women they marry to accept Islam. These Arghons are all Musalmans and, like their fathers, marry Tibetan wives; they are said to be increasing in numbers more rapidly than the pure Tibetan stock. [954] Islam has also been carried into Tibet Proper by Kashmīrī merchants. Settlements of such merchants are to be found in all the chief cities of Tibet; they marry Tibetan wives, who often adopt the religion of their husbands; and there are now said to be as many as 2000 Muhammadan families in Lhasa. [955] Islam has made its way into Tibet also from Yunnan, [956] and at Su-ching, on the border of the Sze-chwan province and Tibet, converts are being won from among the Tibetan inhabitants. [957] Muhammadan influences are also said to have come from Persia [958] and from Turkestan. [959] CHAPTER X. THE SPREAD OF ISLAM IN CHINA. Tradition ascribes to Muḥammad the saying, “Seek for knowledge, even unto China.” [960] Though there is no historical evidence for these words having ever been uttered by the Prophet, it is not impossible that the name of this country may have been known to him, for commercial relations between Arabia and China had been established long before his birth. It was through Arabia, in great measure, that Syria and the ports of the Levant received the produce of the East. In the sixth century, there was a considerable trade between China and Arabia by way of Ceylon, and at the beginning of the seventh century the commerce between China, Persia and Arabia was still further extended, the town of Sīrāf on the Persian Gulf being the chief emporium for the Chinese traders. It was at this period, at the commencement of the Tʼang dynasty (618–907) that mention is first made of the Arabs in the Chinese Annals; [961] they note the rise of the Muslim power in Medina and briefly describe the religious observances of the new faith.