The Rashīdī History 69: RULE OF MIRZA SANIZ IN KASHGHAR AFTER THE DEATH OF HIS FATHER, MIR SAYYID ALI.

69

The Amir died leaving two sons. The elder was Mirza Saniz, whose mother was of the family [kabilah] of the Amirs of the Jaras; and the younger was Muhammad Haidar Mirza, whose mother was Urun Sultan Khanim, the aunt of Yunus Khan. According to Moghul custom, Saniz, being the elder, succeeded to the government. He was a violent, but generous man. Out of respect and reverence for his mother, and his love and affection for his brother, he gave Kashghar and Yangi Hisar to the Khanim, and Muhammad Haidar Mirza [respectively], while he chose Yarkand for his seat of government.
Although Muhammad Haidar Mirza was cousin to both Yunus Khan and Isan Bugha Khan, yet he naturally sided with the latter, because Amir Sayyid Ali had chosen Daulat Nigar Khanim, the daughter of Isan Bugha Khan, as a wife for Muhammad Haidar Mirza.
Soon after the death of Mir Sayyid Ali, Isan Bugha Khan died also; this was in the year 866. His son Dust Muhammad Khan succeeded to the Khanate. Muhammad Haidar Mirza allied himself with Dust Muhammad Khan, while Saniz Mirza, on the other hand, became a partisan of Yunus Khan. Under these circumstances it became impossible for Muhammad Haidar Mirza to remain in Kashghar, so he left, and joined Dust Muhammad Khan in Aksu.
After this, Saniz Mirza governed Kashghar so well, and administered justice so evenly, that his time was looked back on with envy by those who came after him. He ruled during seven years, and died in the year 869 [1464-5]. He fell from his horse while out hunting, and ran five arrow-heads into his loins, causing wounds which proved fatal. After his death, the inhabitants of Kashghar brought Muhammad Haidar Mirza to their town, while Dust Muhammad Khan advanced on Yarkand, where he married the widow of Saniz Mirza, Jamal Agha by name, who had given Saniz Mirza two sons, viz.: Mirza Aba Bakr and Omar Mirza, and one daughter, called Khan Sultan Khanim, all of whom the Khan took back with him to Aksu. (I will speak about them below.)