Genghis, they were initially suppressed in the Yuan Dynasty (1271–1368). Toward the middle and later stages of the Yuan, the Xia received equivalent treatment to the ruling Mongols and attained the highest offices in the Central Court. After the Yuan fell, the Xia who followed the Mongols into the northern grassland were immersed among and later classified into the "Mongols." Tangut-Xixia The English reference of "Tangut-Xixia" was derived from the combination of the Mongolian reference of "Tangut" and the Chinese reference as "Xixia" or "Western Xia." The Chinese reference was derived from the location of the empire on the western side of the Yellow River, in contrast to the Liao (916-1125) and Jin on its east. The Mongolian usage of "Tangut" most likely referred to the "Donghu people;" "-t" in Mongolian language means "people". Whereas "Donghu" was a Chinese transcription, its Mongolian reference was "Tünghu". By the time that the Mongols emerged in the thirteenth century, the only "Donghu people" who existed were the "Tu" in Western Xia. That the Mongols referred to Western Xia as "Tangut" to represent the founding ethnic group, the Tuyühu Xianbei, is consistent with the theories of the Mongol origins postulated by the Outer Mongolian scholars, who have held that the Mongols had descended from the Xiongnu, more specifically the eastern Xiongnu who spoke proto-Mongolic language, as opposed to the western Xiongnu who spoke proto-Turkish language. In contrast, the Chinese scholars have characterized that the Mongols had descended from the Xianbei. The Mongols were recorded as "Mengwu Shiwei" in the Northern Dynasties: "Mengwu" was a variant Chinese transcription of "Menggu" designated to the Mongols, and "Shiwei" was a variant transcription of the Xianbei, as "Xianbei" was also recorded as "Sian-pie," "Serbi," "Sirbi" and "Sirvi". This equated the Mongols to be "Mongol Xianbei," which was likely associated with the submission of the Xiongnu under Xianbei. In 87 A.D., the Xianbei defeated the northern Xiongnu and killed their king, Chanyu Youliu, causing its thorough disintegration. Thereafter, the Xiongnu submitted under and self-proclaimed to be Xianbei. This resulted in a mix of the Xiongnu into Xianbei and made it difficult to differentiate the two groups in subsequent historical records. That the Mongolian term "Tangut" represented "the Donghu people," the Xianbei and their descendants who had founded the Tuyühu and Western Xia empires, would validate the theories of the Outer Mongolian scholars that the Mongols had descended from the