Yujiulü clan
The Yujiulü clan (; reconstructed Middle Chinese: ʔjuk kjǝu ljwo) was the ruling clan of the Rouran Khaganate, which ruled over Northern China, the Mongolian Steppe and Southern Siberia. Origin According to Book of Wei and History of the Northern Dynasties, the surname Yujiulü is of Donghu origin. The first known Yujiulü was a slave caught by Xianbei mounted raiders under the reign of Tuoba Liwei. The slave, whose hairline started at his eyebrows' level, was called Mùgúlǘ (木骨閭) - "bald-headed" in the Xianbei language. When grown-up, Mugulü was noted for his strength, emancipated and recruited as a cavalry soldier. For tarrying past the deadline, he was sentenced to death by beheading. But he fled to the mountains and ravines in the Gobi desert, where he gathered another 100 fugitives. The fugitives sought refuge under the Gaoche tribe called Hetulin (紇突隣). The descendants of Mugulü and his companions became the nucleus of the future Rouran Khaganate. Alexander Vovin proposes that Mùgúlǘ (木骨閭), in reconstructed Middle Chinese *muwk-kwot-ljo, transcribed Tuoba Xianbei *moqo-lo ~ muqo-lo 'bald head', which is analysable as 'one [who/]which has cut-off/fallen-off [hair]' and cognate with Mongolic lexical items like Written Mongolian moɣutur ~ moqutur 'blunt, hornless, bald tail'