Monguor as "Chaghan Monguor" (or "White Mongols"), and "Hour" was a variant record to the Tibetan reference of the Monguor as "Huo’er" used by the Tibetans today. Rise of Tibet In the beginning of the Tang dynasty, the Tuyühu Empire came to a gradual decline and was increasingly caught in the conflict between the Tang and the Tibetan Empire. Because the Tuyühu Empire controlled the crucial trade routes between the east and the west, the Empire became the immediate target of invasion by the Tang. Meanwhile, the Tibetan Empire developed rapidly under the leadership of Songtsen Gampo, who united the Tibetans and expanded northward, directly threatening the Tuyühu Empire. The exile Tuyühu Khan, Dayan, submitted under Tibet, which resorted to an excuse that Tuyühu objected its marriage with the Tang and sent 200,000 troops to attack. The Tuyühu troops retreated to Qinghai, whereas Tibet went eastward to attack the Tangut and reached into southern Gansu. The Tang government was shocked and sent (five ???) troops to fight. Although Tibet withdrew in response, the Tuyühu Empire lost much of its territory in southern Gansu. Meanwhile, the Tuyühu government was split between the pro-Tang and pro-Tibet factions, with the latter becoming increasingly stronger and corroborating with Tibet to bring about an invasion. The Tang sent its famous general, Xue Rengui, to lead 100,000 troops to fight Tibet in Dafeichuan (present Gonghe County in Qinghai). They were annihilated in an ambush by 200,000 troops of Dayan and Tibet, which became the biggest debacle in the Tang history, and formally brought the Tuyühu Empire to an end. After its fall in 670, the Tuyühu Empire split into an Eastern and Western Kingdom. The Eastern Kingdom existed on the eastern side of the Qilian Mountains and increasingly migrated eastward into central China, whereas the Western Kingdom existed under the leadership of the former exile Khan, Dayan, in Tibet. As the An Lushan Rebellion shook up the Tang court and caused its emperor to flee, Tibet overtook the entire territory of Tuyühu until internal turmoil developed within the Tibetan government and massive revolts brought an end to its rule. Through this period, the Xianbei underwent massive diasporas over a vast territory that stretched from the northwest into central and eastern parts of China, with the greatest concentrations found by Mt. Yin near Ordos. In 946, the Shatuo Turk, Liu Zhiyuan, conspired to murder the highest Xianbei