After the fall of the Sui Dynasty, a remnant force moved to the northern border areas, rebuilt the dynasty under the protection of the Turks and existed for ten years, which is the history of the Later Sui, and the "family" of the Later Sui was Yang Zhengdao, the grandson of the Sui Emperor. So, how did Yang Zhengdao form the Later Sui regime? What was his final outcome?
Yang Zhengdao was the grandson of the Sui Emperor Yang Guang and the widow of Yang Huan the Prince of Qi. In March of the fourteenth year of Daye (618), the general Yu Wenhua and the forbidden army led by him launched a mutiny in Jiangdu, killing the Sui Emperor and his clan and foreign relatives, Yang Huan and his second son were killed, Yang Zhengdao was in his mother's womb at this time, and was spared by his grandmother Empress Xiao's intercession with the rebels. Soon, Yu Wenhua and his army of more than 100,000 people, wrapped around the Qin king Yang Hao and Empress Xiao and others, went north, claiming to return to Guanzhong, and Yang Zhengdao was born on the way.
Yang Zhengdao was the grandson of the Sui Emperor and the widow of Yang Huan, the Prince of Qi
Yu Wenhua had the intention of usurping the throne early, and on the way back to the north, he openly occupied the empress dowager of Emperor Jue, and his food, clothing, and living were no different from those of Tianzi ("Hua He then entered the Six Palaces, and his self-worship was just like the story of Emperor Zhao.") See Book of Sui, Vol. 85, Liechuan No. 50, Yu Culture and Liechuan), as if he had regarded himself as an emperor. After being defeated by Li Mi, the leader of the Wagang Army, and retiring to Wei County, Yu Wenhua and himself knew that he was at the end of his rope, so he thought of living the emperor's addiction before dying.
In September of the same year, he deposed Yang Hao and sent people to poison him, and then called himself Emperor Xu, Jianyuan Tianshou, and signed hundreds of officials, openly stealing trumpets in a small county town to entertain himself. After Yu Wenhua and the usurpation, he immediately led his people north to break through, wanting to occupy Wei Prefecture as a base, and after failing, he fled to Liaocheng, but was soon captured by the Hebei warlord Dou Jiande, and was immediately taken to Hejian for execution, in the leap month of the second year of Tang Gaozu Wude (619), only half a year after Yu Wenhua and the usurpation of the emperor.
Yu Wenhua and launched a coup d'état, killing the Sui Emperor, Yang Huan and others
After Yu Wenhua and his army were defeated and killed, Empress Xiao, Yang Zhengdao, and others were once again taken prisoner by Dou Jiande. Fortunately, Dou Jiande was quite polite to them, not only publicly mourning for Emperor Jue and honoring Empress Xiao, but also sealing Yang Zhengdao, who was in his infancy, as the Duke of Yun, and treating him as a foreign monarch, which was enough to give face. Xiao, Yang, and others stayed at Dou Jiande for a year, at which time the Eastern Turkic Luo Khan, at the suggestion of his wife, Princess Yicheng (a sui dynasty patriarchal woman), sent someone to demand Xiao, Yang and others, and Dou Jiande did not dare to offend the Eastern Turks, so he sent them to the Turks.
Chuluo Khan's father, Qimin Khan, once lost his throne, but fortunately he was restored with the support of Emperor Wen of Sui, so he was very grateful to the Sui Dynasty. Because the Sui Dynasty had great kindness to the Turks and the relationship with Princess Yicheng, chuluo Khan was very courteous to Empress Xiao, Yang Zhengdao and others. After Yang Zhengdao arrived in turkistan, Chuluo Khan made him the king of Sui and assigned him to rule over the Central Plains officials and more than 10,000 people who remained in the Territory of Eastern Turkistan.
Empress Xiao led Yang Zhengdao to defect to the Turks and settled in Dingxiang
Yang Zhengdao was stationed in Dingxiang Commandery (定襄郡, in present-day Inner Mongolia and northwestern Linger County), and established a small imperial court here, known in history as the Later Sui Dynasty ("The Turkic Luo Khan welcomed Yang Zhengdao and established himself as the King of Sui.) The Chinese people who are in the north are matched by tens of thousands of people. Hundreds of officials, all in accordance with the Sui system, live in Dingxiang. See Zizhi Tongjian, vol. 188).
After helping Yang Zhengdao to the throne, Chuluo Khan was particularly dissatisfied, and planned to attack the Tang Dynasty south and seize the prefecture to settle Yang Zhengdao, but unfortunately he died of illness before he could send troops, in February of the third year of Wude (620). After the death of Luo Khan and the accession of his brother Jieli Khan to the throne, although Yang Zhengdao was still given preferential treatment, his support for him was much less than before. In this way, Yang Zhengdao awkwardly lived in Dingxiang, and this stay was ten years.
During the reign of Jieli Khan, his support for Yang Zhengdao was much worse than before
Although Jieli Khan did not support Yang Zhengdao's seizure of the prefecture, it did not prevent him from supporting other puppet regimes against the Tang Dynasty, and repeatedly invaded the south, becoming the biggest scourge in the Central Plains. During Tang Gaozu's reign, he was busy with unification and did not have the energy and strength to confront the Turks, but after Emperor Taizong took the throne, the situation changed. In the autumn of the third year of Zhenguan (629), tang taizong sent the military god Li Jing as the commander, with the famous generals Li Ji, Su Dingfang, Chai Shao, and Xue Wanche as deputies, and led an army of more than 100,000 people to attack the Eastern Turks, destroying them in one fell swoop, and capturing Jieli Khan, completely relieving him of his harm to the Central Plains.
After the fall of the Eastern Turks, Yang Zhengdao, who lived in Dingxiang, lost his protection, and the only way left was to surrender. In the first month of the fourth year of Zhenguan (630), Empress Xiao surrendered to the Tang army with Yang Zhengdao, and was subsequently sent to Chang'an, where the Later Sui regime, which had existed for ten years, officially collapsed. Emperor Taizong of Tang gave preferential treatment to these descendants, and not only did he not ask for their lives, but he also made Yang Zhengdao a member of the Outer Scattered Riding Attendant ("And the Turks perished, returned to the Tang Dynasty, and appointed the Outer Scattered Riding Attendant." See Book of Sui, vol. 59, Liechuan 24).
After Yang Zhengdao surrendered to Tang, he was appointed as an official by Emperor Taizong of Tang
Yang Zhengdao later served as a Shangyi Fengyu (for the emperor to manage clothing, for the zhengwu pin official, mostly by the emperor's relatives and relatives), although the official rank is not large, but deeply trusted by the emperor. Yang Zhengdao lived until the early years of Emperor Gaozong's Yonghui of Tang dynasty ("Zhenguan Zhong, the throne to Shangyi Fengyu, Yonghui Chu, died.) See Northern History, Vol. 71 Liechuan No. 59), and his sons Yang Chongli and Sun Yang Shenwei were all prominent officials.