The Mongol conquest of the Dali kingdom began the integration of Yunnan into China proper. The Dali (Ta-li) kingdom (9371253), successor to the Nanzhao (Nan-chao) dynasty (ca. 653902), centered on Dali, the capital, and Yachi (modern Kunming). The administration combined a Chinese system of prefectures and commanderies with the "White Jang" (Mongolian, Chagha'anjang, the modern Naxi) and "Black Jang" (Mongolian, Qarajang, the modern Yi) tribes. The ruling Duan dynasty was of the Chinese-influenced Bai people of Dali, but the "Black Jang" were numerous and powerful. (The idea that the Nanzhao and Dali kingdoms were formed by ethnically Thai peoples is no longer accepted.) Chinese-rite Buddhism was the city dwellers' dominant religion. Along the modern Chinese-Burmese border were the "Gold Tooths" (Persian, Zardandan, named from their gold-plated teeth), ancestors of the modern Dai (Tai) people but not yet Theravadin (Southeast Asian) Buddhist.
Möngke Khan (125159) dispatched Prince Qubilai to Dali in 1253 hoping to outflank the Song. The Gao family, probably Black Jang in origin, dominated the court and resisted. Qubilai took Dali on January 3, 1254, and spared the city, despite the slaying of the Mongol ambassadors. King Duan Xingzhi was confirmed as local ruler, with a Chinese pacification commissioner. After Qubilai's departure back for North China, unrest broke out among the Black Jang, which Uriyangqadai (11991271), son of Sübe'etei Ba'atur, ruthlessly suppressed, butchering Yachi and emptying recalcitrant mountain valleys. By 1256 the pacification was complete, yet difficult frontier conditions made Dali impossible to use for invading the Song.
The mountainous northern parts of the region proved excellent for horses, and Möngke Khan placed the region under 19 Mongol myriarchies. The small Mongol garrisons recruited Black Jang auxiliaries, and in their isolation from the Mongol world the two began to fuse. In 1267 Qubilai Khan (126094) made his younger son Hügechi prince of Yunnan, and in 1273 he dispatched Sayyid Ajall to implement civilian administration in the new Yunnan Branch Secretariat. Mongol Yuan rule in Yunnan was henceforth divided among the imperial princes, the Branch Secretariat under Sayyid Ajall and his family, the Mongol commanders, the Black Jang tribal leaders, and the Duan family in Dali. Yunnan used its distinctive cowrie money throughout the dynasty.
Under Emperor Temür (12941307) a disastrous expedition against the Babai-Xifu in northern Thailand spurred first a local official, Song Longji, and then the Gold-Tooths to revolt in 130103. The revolts were eventually suppressed.
After the expulsion of the Mongols from China in 1368, the Yuan prince Vajravarmi continued to rule Yunnan, refusing relations with the new Ming dynasty. In 1382 the Ming defeated the Vajravarmi's armies and conquered Yunnan. A small population of Mongols (13,148 in 1990), with a heavily Yi (Black Jang)-influenced culture, are a legacy of Mongol rule in Yunnan.