Dawa Norbu argues that modern Chinese Communist historians tend to be in favor of the view that the Ming simply reappointed old Yuan dynasty officials in Tibet and perpetuated their rule of Tibet in this manner. Norbu writes that, although this would have been true for the eastern Tibetan regions of Amdo and Kham's "tribute-cum-trade" relations with the Ming, it was untrue if applied to the western Tibetan regions of Ü-Tsang and Ngari. After the Phagmodrupa Changchub Gyaltsen, these were ruled by "three successive nationalistic regimes," which Norbu writes "Communist historians prefer to ignore."