Wei Zheng left the imperial capital of Chang'an and went to Shandong Province to take up his post. Soon after the crown prince Li Shimin crowned Li Jing and Li Ji, Li Shimin ordered Li Jing and Li Ji to lead their own troops to Jingzhou respectively. Li Shimin's arrangement had two meanings: first, he wanted Li Jing and Li Ji to resist the Turkic attack; The second is to see the reactions of Li Jing and Li Ji, and see if they are willing to obey his orders.

Li Jing and Li Ji did not disappoint the crown prince Li Shimin, both of them received the order, without any hesitation, they led the army westward, trekked all the way, arrived in Jingzhou, and forced the Turkic army back.

Li Shimin praised Li Jing and Li Ji, and promoted them to the title.

A few days later, the right Xiaowei, the left and right leading army of the Wei army commanded by the left leader of the crown prince Li Shimin, Cheng Biting Jin, returned to the imperial capital Chang'an, Li Shimin promoted the position of Xie Shufang, the general of the left and right Jin Wuwei, transferred him from the left and right Jin Wuwei army, and appointed his henchmen Duan Zhixuan and Chai Shao as the left and right Jin Wuwei generals, since then, Li Shimin has controlled the eight guard armies of the imperial capital Chang'an, and has been supported by the other four guards of the imperial capital Chang'an, and has fully controlled the situation in the imperial capital Chang'an.

After that, Li Shimin set his sights on Youzhou and Yingzhou, which were the territory of Li Yi, the king of Yan. Li Yi, the king of Yan, is a figure that Li Shimin is deeply afraid of, he is the most capable general under the prince Jiancheng, with an army of 300,000, and a huge power. Li Yi is the confidant of the prince's henchman, his real surname is Luo, and the prince is the prince who played the Tang Emperor Li Yuan, who gave him the surname Li, in the heart of the prince, Li Yi is more trustworthy than Qi Wang Yuanji, and the prince has recommended and promoted Li Yi many times, and Li Yi is also loyal to the prince, and has repeatedly confronted Li Shimin. In view of the relationship between Li Yi and the crown prince, Li Shimin knew that Li Yi would definitely rebel and avenge the crown prince, as for when to rebel, it was only a matter of time. Li Shimin issued an edict and crowned Li Yi, the king of Yan, as the first lieutenant of the Tang Dynasty, in charge of the Tang Dynasty military, and ordered Li Yi to enter Beijing as soon as possible after receiving the edict. Li Shimin wanted to use this method to prove his judgment.

As he expected, Li Yi was not called, but secretly reorganized his troops and horses, expanded his armaments, and Li Shimin and his advisers knew that Li Yi was preparing to rebel.

August Jiazi is an auspicious day of the zodiac, Li Shimin's enthronement ceremony was held in the Qianyuan Palace, the year is 628 A.D., only fifteen days after Li Shimin was established as the crown prince, Li Shimin did not immediately change the yuan, but continued to use the name of the martial arts until the end of the year.

Li Shimin's crown princess and eldest grandson Wuji's younger sister Changsun was made the queen, and Li Shimin's concubine and the daughter of Emperor Yang Guang of the Sui Dynasty Yang Guang was made Yang Concubine and the head of the "four concubines", and her status was only below the queen's eldest grandson.

Feng Deyi was crowned as the second rank of the servant, becoming the highest official in Menxia Province, ranking in the high position of Zaifu, and Xiao Yu was crowned as the secretary of the second grade, becoming the highest official in the secretary province, and also ranked in the high position of Zaifu. The Tang Dynasty implements the system of three provinces and six ministries, Menxia Province is one of the three provinces, Menxia Province is the think tank of the Tang Emperor, the country's major policies are all from Menxia Province, and the highest officials often accompany the Tang Emperor around, giving advice to the emperor, praising and guiding public affairs, and consulting to deal with them; The secretary province, officials who are familiar with the central organs of the Tang Dynasty, all know that the three provinces and six ministries system implemented by the Tang Dynasty are actually six provinces and six ministries, and the other three provinces are the secretary province, the palace province, and the inner service province, and the highest official of the secretary province is the secretary supervisor. The palace province is responsible for the life of the emperor, and consists of the Shang Food Bureau, the Shang Medicine Bureau, the Shang Yi Bureau, the Shang She Bureau, the Shang Tby Bureau, and the Shang Yuan Bureau, which manage the clothing, food, housing and transportation of the Tang Emperor; The Ministry of the Interior was responsible for managing the internal affairs of the palace. Since the secretary province, the palace province, and the inner service province all serve the emperor personally, everyone tacitly skipped it and declared that the Tang Dynasty implemented a system of three provinces and six ministries. The secretary of the province, the palace province, the highest officials of the province are called the supervisor, the palace supervisor, the inner chamberlain are the three high-ranking officials, and the secretary supervisor is from the second grade, because the secretary is in charge of the Tang Dynasty's books and classics for the emperor to inquire, often the secretary supervisor has more court Confucianism, there are literary names, prestige ministers to serve, the Tang Emperor also respects it very much, not only the official position is slightly higher than the palace eunuch, the inner chamberlain, and the secretary is also known as the prime minister, all the national policies of the Tang Dynasty, the secretary supervisor has the right to participate, and put forward their own opinions.

Li Shimin's confidant, Wang Fugui, a personal eunuch, was promoted to the post of Zhengsanpin Inner Attendant and became the highest official in the Inner Servant Province. Li Shimin's favorite general, the right servant of the Shaanxi East Dao Xingtai, was appointed by the Tang Emperor Li Shimin to stay in the eastern capital of Erpin and guard the eastern capital Luoyang. Fang Xuanling, Du Ruhui and other Li Shimin's henchmen were successively recalled to the imperial capital Chang'an.

Li Xuan was crowned as the national teacher of Zhengyipin and continued to give advice to the Tang Emperor Li Shimin. Gao Shilian was still the secretary of the ministry, but the number of restaurants increased by 600. The eldest grandson Wuji did not have a reward, but all the officials in the imperial capital Chang'an knew that the eldest grandson Wuji was the upstart of the Tang Dynasty, and the eldest grandson Wuji was not only a confidant of His Majesty the Emperor, but also conspired against His Majesty the Emperor, and he was also the only brother of the current queen.

On the second day after the Tang Emperor Li Shimin ascended the throne, Li Yi set up an anti-banner in Youzhou and officially raised troops against the Tang Dynasty and opposed Li Shimin's rule.

Li Shimin issued an edict appointing Li Jing as the marshal, Qin Qiong, Wei Chi Jingde, Cheng Yanjin, Zhang Gongjin, Duan Zhixuan, and Li Ji as generals, leading a total of 300,000 troops to defeat the rebellious Yan King Li Yi. Li Shimin knew that only by completely defeating Li Yi with the fastest speed and the most powerful strength could he establish his prestige and deter the Quartet, so he sent the most capable Li Jing and almost all of his own forces, but he was not very at ease with Li Jing, and appointed his henchmen Qin Qiong, Wei Chi Jingde, Cheng Yanjin, Zhang Gongjin, and Duan Zhixuan as checks and balances, and appointed his henchmen and personal guards Duan Chang as the supervisor in case Li Jing had two hearts. Duan Chang is only thirty years old this year, but he has followed Li Shimin since he was very young, and has used his body to resist the sword for Li Shimin many times, and he is Li Shimin's diehard loyal.

Li Jing commanded the army and slowly left the imperial capital Chang'an, and in Chang'an City, only the left and right Qianniuwei led by Hou Junji and the right Jin Wuwei and the three guards led by Chai Shao guarded the imperial capital Chang'an, with less than 30,000 people.