Illig Qaghan (Old Turkic: ; ), born Ashina Duobi (), posthumous name Prince Huang of Guiyi (歸義荒王), was the last qaghan of the Eastern Turkic Khaganate. Background He was a son of Yami Qaghan and his Tuyuhun wife Poshi (婆施). He was raised by the Tuyuhun general Külüg Tarkhan (胡祿達官). After coming of age, he was given the title Baghatur shad (莫賀咄設) and was assigned to rule the eastern parts of the empire. Reign He declared himself Illig Khagan after the death of his older brother Chuluo and married his brother's widow as well. He gave his nephew Ashina Shibobi the title of Tolis Qaghan afterwards and assigning him to his own former tribes. He continued his predecessors' pro-Sui politics, supporting puppet emperors. Raids into Tang His first contacts with Tang were very hostile. In 621, Tujue forces attacked Fenyin and Xi territories, reaching as south as Yanmen in April. As a response, Turkic ambassadors were arrested in China and vice versa. In May, khagan's forces crushed Tang forces commanded by Li Shuliang (李叔良), Gaozu's cousin who died from arrow wounds after a month. They were repelled later by Yang Shidao. Later raids were accompanied by Gao Kaidao and Yuan Junzhang (苑君璋), a general formerly under Liu Wuzhou. To stop raids, Gaozu offered khagan a tribute and a Chinese princess. Khagan accepted the proposal and both states released arrested envoys. Soon raids restarted, in 623, khagan were assisted by Gao Kaidao and Liu Heita in sieging Mayi (present-day Shuozhou, Shanxi) and capturing it. Yuan Junzhang was appointed governor of Mayi. But Mayi was soon reverted by Tujue in hopes of attaining a marriage to Tang princess. Later Liang Luoren (梁洛仁), the brother of Liang Shidu attacked with assistance from Eastern Tujue to Ling prefecture. However Li Daozong (a cousin of Taizong) was able to repel him, and further expel the khagan's nephew Ashina Yushe (阿史那郁射) from the Wuyuan (五原, in modern Yulin, Shaanxi). As raids were becoming more frequent in 624, Li Shimin stepped up to accuse Ashina Shibobi of breaking his brotherhood vows, which made Illig Khagan to grow suspect towards Shibobi. Khagan soon attempted to seek peace, sending his nephew Ashina Shibobi and his uncle Ashina Simo to negotiate. In 625, khagan attacked Ling Prefecture (靈州, roughly modern Yinchuan, Ningxia). Emperor Gaozu sent the general Zhang Jin (張瑾) to resist Tujue with Wen Yanbo serving as Zhang's secretary