The Khitan, in Chinese Qidan (契丹 Pinyin: Qìdān) ), were an ethnic group who dominated much of Manchuria and classified in Chinese history as one of the Tungus ethnic groups (東胡族 dōng hú zú). They established the Liao dynasty in 907. Kara-Khitai is the name given to the remnants of Khitans who escaped the conquest of the Jurchens and migrated to the Kara-Su. Their new regime was named Kara-Khitan Khanate with capital at Balasagun.
Ancestors of Khitans was the Yuwen clan of the Xianbei. After their regime was conquered by the Murong clan, the remnants scattered in today Inner Mongolia and evolved into Khitan through intermarriage. They had been identified as a distinct ethnic group since paying tribute to the Northern Wei Dynasty in mid 6th century .
The Khitan were known as خطا in Arabic (Khata) and are mentioned by Muslim chroniclers as they initially fought with Muslims and later converted to Islam.
Khitan also refers to the now-extinct language once spoken by the Khitan people. There were two writing systems for the Khitan language, known as the large script and the small script; they were functionally independent. The former was derived from Chinese, and the latter was apparently inspired by the Uighur alphabet.
The Khitan language is most probably Mongolic, however, and its agglutinizing nature is not particularly suited to purely monosyllabic logographs. The small script had logographs as well as characters which were completely phonemic. The Jurchens (ancestors of the Manchu people) derived their large script in part from Khitan.
See also: Ethnic groups in Chinese history, Kara-Khitai