The Liao Dynasty; also known as the Khitan Empire; was a state that ruled over the regions of Manchuria; Mongolia; and parts of northern China proper. It was founded by the Yel眉 clan of the Khitan people in the same year as the Tang Dynasty collapsed (907); even though its first ruler; Yel眉 Abaoji (Yaruud Ambagai Khan); did not declare an era name until 916.

Although it was originally known as the Empire of the Khitan; the Emperor Yel眉 Ruan officially adopted the name 'Liao' (formally 鈥楪reat Liao') in 947. Another name for China in English; Cathay; is derived from the name Khitan. This is also the origin of the Russian word for China; ????? or Kitay; and that of several other East European languages.

The Liao Empire was destroyed by the Jurchen of the Jin Dynasty in 1125. However; remnants of its people led by Yel眉 Dashi established the Xi (Western) Liao Dynasty 1125-1220; also known as Kara-Khitan Khanate; which extended its influence over Central Asia into Persia and survived until the arrival of Genghis Khan's unified Mongolian army.