Emperor Xingzong of Liao

Yelü Zongzhen was the eldest son of Emperor Shengzong. He was born to a court lady named Xiao Noujin (萧耨斤) but was raised by the Empress Xiao Pusage (萧菩萨哥), the niece of Zongzhen's grandmother Xiao Yanyan. He was enfeoffed as a prince in 1021 at the age of six. When Emperor Shengzong died in 1031, Yelü Zongzhen succeeded his father as emperor. His mother Xiao Noujin became consort dowager and his adopted mother Xiao Pusage became Empress Dowager.

After receiving this title, Xiao Noujin became arrogant and gave herself the new title of Empress Dowager despite being a former concubine. She was longtime rivals with Xiao Pusage, and spied on Xiao Pusage several times when Zongzhen was a prince. Xiao Noujin tried persuading her son to get rid of Xiao Pusage, but he refused to comply since Xiao Pusage had no children and raised him as a child. When the Emperor was occupied with a hunting trip, Xiao Noujin sent assassins to murder Xiao Pusage.

The Emperor's reign was controlled by his mother Xiao Noujin. She was very ambitious and didn't want her power at court to be diminished. Although she promised Emperor Jingzong to be content with her title of Consort Dowager, she issued a false edict stating that she was an Empress Dowager. She had plans for her younger son Zhongyuan to replace Zongzhen on the throne. Yelu Zhongyuan told his brother, and Xiao Noujin was sent away from the palace. After the Emperor's death, Xiao Noujin reportedly told her daughter-in-law Empress Xiao Dali not to mourn.

The Sinified form of his personal name is usually given as the reason (via the Chinese naming taboo) for the variant forms of the Chinese name of the Jurchens around this time. More likely, however, the variants—which are also attested in other languages of the era lacking such a taboo—simply reflect dialectical differences among the Jurchens themselves.

Emperor Xingzong's reign was the beginning of the end for the Liao dynasty. The government was corrupt and the army started to fall apart. He attacked the Western Xia dynasty many times, and waged war against the Northern Song dynasty. However, the frequent wars were not looked kindly upon by his people, and there were much anger among them for the high taxes. Although Emperor Xingzong was successful in bullying Song into raising the annual indemnities, he was unsuccessful in his invasion of Western Xia due to sandstorms. Emperor Xingzong was interested in Buddhism and spent lavishly for his own pleasure. He died in 1055 and was succeeded by his son Emperor Daozong.