Liang Shidu
Liang Shidu was a claimant to title of Emperor of China who rebelled against the rule of the Chinese Sui dynasty near the end of the reign of Emperor Yang of Sui. Liang Shidu claiming the title of Emperor of Liang with the aid from Eastern Turkic Khaganate retained the modern northern Shaanxi and western Inner Mongolia region for over a decade, but was gradually weakened by attacks from the Tang dynasty, whose founding emperor Emperor Gaozu and successor Emperor Taizong had eliminated the rival contenders for power one by one, leaving Liang isolated. In 628, with the Eastern Turks in internal turmoil and unable to come to his aid, Emperor Taizong launched another attack on Liang. Liang's cousin Liang Luoren assassinated him and surrendered, completing Tang's drive to reunite China after Sui's collapse.
Initial uprising
Liang Shidu was from a prominent clan of Xia Province, and during the reign of Emperor Yang of Sui, he served as a military officer. In or shortly before 617, he quit the army and returned to his home commandery. At that time, there were many agrarian rebellions in the region, and Liang gathered a group of men to create a local protective force. He later ambushed the secretary general of Shuofang Commandery, Tang Shizong. He initially claimed the title of Grand Chancellor imitating Emperor Wen of Sui who also acted as a regent to a boy emperor before him.He later entered into an alliance with Eastern Turkic Qaghanate. When the Sui general Zhang Shilong tried to attack him, he defeated Zhang. He thereafter captured several other nearby commanderies — Diaoyin, Honghua, and Yan'an. He submitted to Eastern Türks' Shibi Khan, who created him the Dadupiqie Qaghan and bestowed on him a flag with a wolf head, the symbol of the Türks. He guided Eastern Tujue forces to occupy the Ordos Desert region. Subsequently, Shibi Qaghan gave him a Chinese regnal name Jieshi Tianzi for Liang as a translation for his Turkic title, although he himself declared a state of Liang and himself its emperor with era name Yonglong.
Early reign
Liang Shidu entered into an alliance with another rebel leader of the region, Guo Zihe. In 618, with the Sui general Li Yuan having rebelled against Emperor Yang and entered the capital Chang'an, declaring Emperor Yang's grandson Yang You emperor, another rebel ruler, Xue Ju the Emperor of Qin, entered into an alliance with Liang and Eastern Türks, seeking to attack Chang'an. However, Li Yuan was able to persuade the Eastern Türk general Ashina Duobi to give up the campaign. In fall 618, with Li Yuan having had Yang You yield the throne to him, establishing the Tang dynasty as its Emperor Gaozu, Liang tried to attack Ling Prefecture, which had submitted to Tang, but was repelled.In spring 619, Shibi Qaghan was planning on a major incursion into Chinese territory, and both Liang and another rebel ruler, Liu Wuzhou, joined him. However, Shibi Qaghan died and his brother Ashina Xichun succeeded him, who terminated the campaign after receiving a large tribute from Tang. Liang then again attacked Ling Prefecture but was again repelled. In fall 619, he attacked Yan Prefecture, which had submitted to Tang as well, but was repelled by the Tang general Duan Decao. Another Liang attack in fall 620, in conjunction with Eastern Türks, was also repelled by Duan. Meanwhile, Liang's one-time ally Guo Zihe, who had submitted to Tang as well, had turned against Liang and Eastern Türks, seizing Liang's city of Ningshuo. Eastern Türks, in response, imprisoned Guo's brother Guo Zisheng, and Guo subsequently moved south to avoid Eastern Türk forces.
Meanwhile, with his generals Zhang Ju and Liu Min having defected to Tang and with Liu Wuzhou having been defeated by Tang earlier in 620, Liang was fearful that he would become next, and he sent his official Lu Jilan to point out to Chuluo Qaghan that he should act against Tang before it became too strong to control. Qaghan agreed, and made a grand plan to attack Tang on several sides, incorporating Xi tribe forces and those of another rebel ruler, Dou Jiande the Prince of Xia, into the plan. According to this plan, Baghatur Shad would enter Wuyuan, Nipu Shad and Shidu would proceed to Yanzhou, while Chuluo Qaghan himself would attack Taiyuan, have Ashina Shibobi join with the Xi, Kumo Xi, Khitan, and Mohe on the Youzhou road, and have Dou Jiande join at Jinzhou and Jiangzhou from Fukou. However, before Qaghan could launch his plan, he died. He was succeeded by Ashina Duobi as Illig Qaghan who arrested the Tang Minister of Ceremonies Zheng Yuanshu on suspicion of poisoning the qaghan.
In spring 622, Duan launched an attack on Liang, capturing the eastern city of Liang's capital Shuofang, forcing Liang to withdraw to the western city. However, relief forces from Eastern Türks arrived, and Duan withdrew. Liang subsequently sent his brother Liang Luo'er with Eastern Türk forces, to attack Tang's Ling Prefecture, but was repelled by the Tang general Li Daozong.
Late reign
He was the last Chinese rebel to stand against Tang. In spring 623, Liang Shidu's generals He Sui and Suo Tong defected to Tang, along with the territory they controlled. In summer 623, Duan Decao launched another attack on Liang, reaching Shuofang, but withdrew after pillaging. In response, the Liang general Xin Liao'er guided Eastern Türk troops to attack Tang's Lin Prefecture, and then Liang himself guided Eastern Türk forces to attack Tang's Kuang Prefecture. Around this time, the Qihu chieftain Liu Yaocheng came to submit to the Liang state, but Liang Shidu instead turned on him and annexed all his forces, causing his own officers to become fearful and distrustful of him. In fall 624, the major Liang official Bai Fuyuan defected to Tang.In 626, Emperor Gaozu's son Li Shimin the Prince of Qin, ambushed and killed his brothers Li Jiancheng the Crown Prince and Li Yuanji the Prince of Qi, and then effectively forced Emperor Gaozu to yield the throne to him. Meanwhile, Liang himself saw his forces weakening, and suggested to Illig Qaghan that he invade Tang. Illig and his nephew, the subordinate Ashina Shibobi jointly attacked the Tang capital Chang'an, but withdrew after Emperor Taizong personally met them and offered additional tributes.
Death
In 628, Emperor Taizong of Tang, seeing that internal Turkic turmoil prevented them from aiding Liang Shidu, wrote a letter urging him to surrender, but Liang Shidu firmly refused. The emperor then ordered Liu Min, the Military Administrator and Chief Clerk of Xiazhou, and Liu Lancheng, the Marshal, to prepare for an attack. He also employed a stratagem to bribe and recruit Liang's civil and military officials. Liang Shidu's general Li Zhengbao once planned to capture Liang Shidu and surrender to Tang, but when Liang Shidu discovered this, Li fled and surrendered to Tang instead. Taizong sent raiding forces to pillage Liang periodically, as well as to burn the crops, reducing Liang's food supplies, and also sent agents into Liang territory to damage the relationships between Liang and his officials. In summer 628, when a number of Khitan tribes surrendered to Tang, Illig Qaghan offered to trade Liang for the Khitan tribes, but Emperor Taizong refused.That same year, Emperor Taizong deemed the time ripe and ordered his brother-in-law Chai Shao and Palace Attendant Supervisor Xue Wanjun to lead a major military campaign against Liang Shidu, while also dispatching Liu Min to press toward the eastern city of Shuofang. Liang Shidu sent troops to meet the attack but was defeated by the Tang general Liu Lancheng, and Turkic reinforcements were also crushed by Chai Shao. Later the food supplies ran out, Liang Shidu's cousin Liang Luoren assassinated Liang Shidu and surrendered the city to Tang. Exact death date of Shidu is conflated in sources. Emperor Taizong's biography in Old Book of Tang indicate that Liang was killed on the bingshen day of the 4th month of the 2nd year of the Zhenguan era of Emperor Taizong's reign; this corresponds to 28 May 628 in the Julian calendar. Taizong's biography in New Book of Tang and Zizhi Tongjian both dated Liang's death to the rényín day of that month, which corresponds to 3 June 628 in the Julian calendar.
Liang Luoren's action was considered an immense service to the Tang Dynasty, as it secured the final regional rival without a prolonged siege. The Tang court rewarded him generously. He was given the military position of General of the Right Fearless Guards and was granted the title Duke of Shuofang County, a noble title named after the very city he surrendered.