History of Liao
Yelü Longxu, posthumously Emperor Shengzong of Liao, succeeded his father, Emperor Jingzong of Liao. He was only 11 years old at the time of his father's death so actual power fell to the regent, his mother Xiao Yanyan. Until her death in 1009, the Khitan empire was ruled by her and three ministers, two of whom were Chinese. Xiao Yanyan was an extremely capable ruler, being both astute in politics and warfare, commanding an ordo to herself capable of fielding 10,000 cavalry. According to the "History of Liao", "most of his [Shengzong] success must be attributed to his mother's instruction."