Puxian Wannu originally served the waning Jin dynasty under pressure from the Mongol Empire. While the Mongols under Genghis Khan invaded Jin, a Khitan chief Yelü Liuge (耶律留哥) revolted against the Jin dynasty in Liaodong in 1211 and made contact with the Mongol Empire in the next year. In 1214, the Jin dynasty dispatched Puxian Wannu to Liaodong, but he was defeated around Kaiyuan. While Mukhali of the Mongol Empire invaded Northern China and captured the Jin capital Zhongdu, Puxian Wannu rebelled against the Jin dynasty and founded the Eastern Xia dynasty in Dongjing (Liaoyang) in 1215 with the support of the Mongols. During that year, as a vassal, he sent his son Tege (帖哥/鐵哥 Tiěgē) as a hostage to the Mongols in 1216. He adopted the title of Tianwang (天王 lit. Heavenly King) and named his era Tiantai (天泰). He also established the government institutions based on the Jin systems. Although he originally acknowledged his allegiance to the Mongol Empire, he however rebelled against the Mongols and killed the Mongolian resident commissioners in 1217. He also moved the capital to Nanjing (南京 literally: "southern capital") in modern day Mopancun Fortress near Yanji, Jilin province. In 1233, Güyük (then a prince) was dispatched by Ögedei Khan to conquer the Eastern Xia. Puxian Wannu was captured and killed in the same year, which marked the official end of the Eastern Xia kingdom. The Jin dynasty was also conquered by the Mongols in the next year.
The actual name of the kingdom is controversial. Chinese documents call it Dongxia (东夏/東夏) but Goryeo almost always called it Dongzhen (東眞). Yanai Wataru insisted that Xià (夏) was a misinterpretation of Zhèn (眞). In the meanwhile Ikeuchi Hiroshi claimed that Dongzhen was an abbreviated form of Dong Nüzhen (东女眞/東女眞, Eastern Jurchen) and was just an alias.
