 In 634 one of their rivals, Dubu Qaghan (Ashina Shier), son of Chuluo Khan, who ruled much of the eastern half of the Western Qaghanate, was eliminated before escaping to China.After that they maintained a friendly relationship with the Chinese until 639, when a raid on the Chinese capital was planned by the Gökturks under Ashina Jiesheshuai (阿史那结社率), who had been disparaged by the Chinese emperor.He allied with his nephew Ashina Heluohu (阿史那贺逻鹘), choosing him as the leader of the raid on May 19.