Emperor Taizong, after becoming emperor, became suspicious as to whether his older brother intended to take back the throne, and therefore moved Dongdan's capital to Dongping (東平, in modern Liaoyang, Liaoning) and forcibly moved the former Balhae people to Dongping. He also put guards in place to monitor Yelü Bei's actions. When Emperor Mingzong of Later Tang heard this, he sent secret emissaries encouraging Yelü Bei to flee to Later Tang. Yelü Bei, commenting, "I yielded the empire to the Emperor, but now I am under suspicion. It is better that I go to another state so that I can be like Wu Taibo." He thus took his favorite concubine Lady Gao and his extensive book collection, got into a ship, and sailed to Later Tang. In 930, he arrived at Later Tang's Deng Prefecture (登州, in modern Yantai, Shandong). (Yelü Bei's wife Imperial Queen Xiao and his oldest son Yelü Ruan did not follow him to Later Tang, and Imperial Queen Xiao would subsequently continue to rule the Dongdan state until her death in 940, while Yelü Ruan would eventually succeed Emperor Taizong after his death (as Emperor Shizong).)