According to Chinese annals, by this point, his territory stretched from the Mohe to the east, Western Turks to the west, and Gobi Desert to the south, and that many tribes, including Huige (回纥), Bayegu (拔也古), Adie (阿跌), Tongluo (同羅), Pugu (僕骨), and Baixi (白霫), all submitted to him.

[2] Emperor Taizong, believing that Xueyantuo was becoming strong and difficult to subjugate, created both Bazhuo and Jialibi as subordinate khans under their father, awarding them both drums and banners, ostensibly to honor them, but hoping to instead cause dissent between them.

[10] Meanwhile, Qu Wentai (麴文泰), the king of Gaochang, was rumored to have allied himself with Western Turks against Tang, and also tried to engage Xueyantuo in their alliance, sending an emissary to Zhenzhu to incite him to invade China.

Emperor Taizong sent the official Tang Jian and the general Zhishi Sili (執失思力) to Xueyantuo, to award Zhenzhun with silk for his loyalty and to discuss coordination.

He sent Guo Siben,[12] Chief Minister of Granaries[13] to Zhenzhu, explaining the reasons and ordering Xueyantuo to keep peace with the rebuilt Eastern Turkic Khaganate.

Zhenzhu, who was reminded that he was the senior khagan, while displeased with the action, agreed to buy time,[14] and by 641, Qilibi Khan had settled in near Dingxiang (定襄, in modern Hohhot, Inner Mongolia).

Later that year, believing that Emperor Taizong was about to offer sacrifices to heaven and earth at Mount Tai and would take his soldiers with them, Zhenzhu Khan wanted to use this chance to destroy Turks.

He commissioned his son Dadu shad (大度設),[3] with an army made of soldiers from the Tongluo, Pugu, Uyghurs, Mohe, and Xi, to attack Eastern Turks with 200,000 men.

Qilibi could not resist, and withdrew within the Great Wall, took up position at Shuo Prefecture (roughly modern Shuozhou, Shanxi), and sought emergency aid from Emperor Taizong.

He appointed Minister of War Li Shiji as the chief commander of Shuozhou campaign, leading 60,000 soldiers and 1,200 cavalry to camp at Yufang.

Xueyantuo on the other hand, trained their troops in infantry combat, forming units of five where one person held the horse while the other four fought on foot.

Although Taizong was planning about full campaign, Wei Zheng advised against it, leading to the decision to refrain from further military action against Xueyantuo.

He sent his uncle Ishbara Nishu Irkin[16] (Chinese: 沙缽羅泥孰俟斤; pinyin: Shābōluó Níshú Qíjīn) in 642 to Emperor Taizong, offering a tribute of 3,000 horses, 38,000 mink coats, and a mirror made of amber.

In 643, Zhenzhu accepted to these terms and this time sent his nephew Tuli shad (Chinese: 突利設; pinyin: Tūlì Shè) to offer tributes of 50,000 horses, 10,000 cattle or camels, and 100,000 goats, to serve as bride price.

When Zhenzhu agreed to go to Ling Prefecture, Emperor Taizong found another excuse—that the bride price offered had not been all collected (as, in order to gather the livestock making up the bride price, Zhenzhu had to collect them from subordinate tribes, and it was taking longer than thought, and the livestock were also dying from having to go through the Gobi) -- to cancel the marriage treaty, despite strong opposition from his official Chu Suiliang, who pointed out that, effectively, he was devaluing his own words.

Emperor Taizong rationalized his decision by arguing that if Zhenzhu had married a Tang princess, he would have greater legitimacy over the Tiele tribes and would be more difficult to control.

I, having received deep grace, request permission to exterminate them for Your Majesty.By the end of 644, the Eastern Turks people, who were not whole-heartedly supportive of Qilibi Khan in the first place, collapsed in light of Xueyantuo threat, fleeing back to Tang territory, and were again settled there.

It was said that khan, with Tang permission, had previously created his oldest son by a concubine - Yemang a Tolis Shad - a title traditionally given to subrulers of eastern wing, to govern over various tribes, and his wife's son Bazhuo Si Yabgu Khan, giving him the western parts, to govern over the Xueyantuo people, and that Emperor Taizong had carried out the creation in grand ceremonies.