Yelü clan

The Yelü clan (Chinese: 耶律; pinyin: Yēlǜ; Khitan small script: ) of the Khitan people assumed leadership of the Khitan nation in 907 when Abaoji became khan of the Khitan nation. The clan, written "ei.ra.ú.ud" in the Khitan language, maintained that leadership through the fall of the Liao dynasty in the 1120s. Even following this fall, members of the clan appear in history, most notably during the Mongols era of conquest in the thirteenth century.

Abaoji, born in 872, was the son of the chieftain of the Yila tribe. At this time, the Yaolian clan had led the Khitan people since the mid-eighth century, and were the only Khitan family to have adopted a surname at this point as this was seen as a mark of Chinese culture and not befitting of peoples of the steppe.

In 901, Abaoji was elected chieftain of the Yila tribe and in 905 forged relations with Li Keyong of the Shatuo Turks. In 907, he was chosen leader of the Khitan, the first outside the Yaolian lineage to be chosen in more than a century and a half. From this, Abaoji and his successors developed the Liao dynasty, which would conquer all of Manchuria, the northern fringe of China known as the Sixteen Prefectures and adjacent areas of northern Korea, eastern Mongolia and parts of far-eastern Russia.

...
Wikipedia