In 626, Emperor Gaozu's son Li Shimin the Prince of Qin, who had been in an intense rivalry with his older brother Li Jiancheng the crown prince, ambushed and killed Li Jiancheng and Li Yuanji, the Prince of Qi, at Xuanwu Gate. He then forced Emperor Gaozu to first enfeoff him as crown prince and then abdicate the throne, leaving it open for Li Shimin to take the throne as Emperor Taizong. After Taizong ascended to power in 628, Ashina Tong was killed by his uncle, Ashina Moheduo, who seized the throne as Qulipiqie Khan. However, some key Turks supported Ashina Tong's son Ashina Dieli as khan. Both sought aid and marriages from Tang China, and Emperor Taizong declined both. Eventually, in 630, Ashina Dieli was able to defeat and kill Ashina Moheduo, again reuniting the Western Turkic Khaganate. Meanwhile, Gaochang's king Qu Wentai made a visit to Chang'an in 630, and was received warmly by the Tang court.