遼史
Genetically, the Daurs are descendants of the Khitan, as recent DNA analyses have proven. In the Qianlong Emperor's "钦定《辽金元三史语解》" (Imperially commissioned Translations of the History of Liao, History of Jin and History of Yuan) he retranslates "大贺", a Khitan clan described in the History of Liao, as "达呼尔". That is the earliest theory that claims Daurs are descendants of Khitans.