But there is certainly no distinct evidence of any proselytising activity on the part of the Muslims in China, and indeed very little information about them at all until the period of Mongol conquests, in the thirteenth century. These conquests resulted in a vast immigration of Musalmans of various nationalities, Arabs, Persians, Turks and others into the Chinese empire. [972] Some came as merchants, artisans, soldiers or colonists, others were brought in as prisoners of war. A large number of them settled permanently in the country and developed into a populous and flourishing community, which gradually lost its original racial peculiarities through intermarriage with Chinese women. Several Muhammadans occupied high posts under the Mongol rulers, e.g. ʻAbd al-Raḥmān, who in 1244 was appointed head of the Imperial finances and allowed to farm the taxes imposed upon China, [973] and ʻUmar Shams al-Dīn, commonly known as Sayyid Ajall, a native of Bukhārā, to whom Qūbīlāy Khān, on his accession in 1259, entrusted the management of the Imperial finances; he was subsequently governor of Yunnan, after this province had been conquered and added to the Chinese empire. [974] Sayyid Ajall died in 1270, leaving behind him a reputation as an enlightened and upright administrator; he built Confucian temples as well as mosques in Yunnan city. [975] The descendants of Sayyid Ajall played a great part in the establishing of Islam in China; it was his grandson who in 1335 obtained from the emperor the recognition of Islam as the “True and Pure Religion”—a name which it has kept to the present day,—and another descendant of Sayyid Ajall was authorised by the emperor in 1420 to build mosques in the capitals, Si-ngan-fu and Nan-kin. [976]