The Rashīdī History 9.1.4

9.1.4

On the partition of the empire of Chingiz Khan among his sons, we read of Uighuristan falling to the appanage of Chaghatai Khan, and we also learn, from Mirza Haidar, of Chaghatai having entrusted the province called 'Mangalai Suyah,' as far east as Chalish, to the care of the Dughlats, but not a word is said regarding the disposal of the districts to the eastward of Chalish. Referring to a later date—about 1320—Abul Ghazi mentions Uighuristan as one of the countries, the inhabitants of or Uighuristan, which, being without a Khan at that time, summoned Isan Bugha I. from Mawara-nn-Nahr to reign over them. But although a region is often mentioned by this name subsequent to the time of Chingiz, no indication, as far as I am aware, is given of its situation, until we come to Mirza Haidar's incidental statement that it constituted the eastern neighbour of 'Mangalai Suyah,' and was, consequently, identical with the Khanate of 'Chalish and Turfan.' On the other hand, though the Khanate is mentioned by Erskine, he does not connect it with the Uighuristan of Asiatic authors, but speaks of it always as 'the Eastern districts' — presumably of the Moghul Khanate in general. Mirza Haidar, unfortunately, omits to apprise his readers of the extent of the Khanate of Uighuristan. At periods when Aksu was not comprised within its limits, it could not have been large.