The Rashīdī History 4.2.6

4.2.6

But a rival was beginning to show himself in the person of Kaidu, a grandson of Oktai. This prince was plotting, in western Kipchak, for the assistance of his uncle Batu, in asserting his claim to the province of Turkistan—the north-western division of the Chaghatai Khanate—and probably also for the region then becoming known as Moghulistan, which lay immediately to the eastward of Turkistan, and comprised the Zungar country, already alluded to. At the death of Algu, Kublai nominated Mubarak Shah, a son of Algu and Organah, to the Chaghatai succession, but immediately afterwards is said to have appointed, as his vice-regent, another great-grandson of Chaghatai, named Borak (or Barák), to support Mubarak Shah in resisting Kaidu. So far from assisting the young Khan, Borák drove him from the throne, made common cause with Kaidu, and for a time exercised joint sovereignty with the latter over Transoxiana. But jealousies were not long in showing themselves between the allies, and quarrels ensued which were only partially composed at a kuriltai, or conference of the chiefs of the tribes, held in Turkistan in 1269, when certain points were agreed on, the most important being "the implied recognition of Kaidu as the rightful Khakan of the Moghuls, which from this time was extended by the Chaghatai Khans both to him and his son Chapar."