Empress Zhangsun - As Princess of Qin and Crown Princess

As Princess of Qin and Crown Princess

In 617, Li Yuan, aided by Li Shimin and his older brother Li Jiancheng, among others, rebelled at Taiyuan (太原, in modern Taiyuan, Shanxi), and later that year captured the capital Chang'an, declaring Emperor Yang's grandson Yang You the Prince of Dai emperor (as Emperor Gong). In 618, after news arrived that Emperor Yang had been killed in a coup at Jiangdu (江都, in modern Yangzhou, Jiangsu) led by the general Yuwen Huaji, Li Yuan had Emperor Gong yield the throne to him, thus establishing the Tang Dynasty. Li Yuan became the first Tang ruler, Emperor Gaozu. He appointed his son, Li Shimin, as the Prince of Qin, his wife as the Princess of Qin. The couple would eventually have three sons – Li Chengqian, Li Tai, and Li Zhi – and at least three daughters, who were later named the Princesses Changle, Jinyang, and Xincheng.

Li Shimin was Tang's most capable general in its campaigns to reunite China following Sui's collapse, defeating the major enemies Xue Rengao the Emperor of Qin, Liu Wuzhou the Dingyang Khan, Wang Shichong the Emperor of Zheng, and Dou Jiande the Prince of Xia. In doing so, he overshadowed his older brother Li Jiancheng, the crown prince. The brothers developed an intense rivalry. Princess Zhangsun was said to serve her father-in-law Emperor Gaozu carefully while trying to reduce the adversarial nature of the brothers' relationship (unsuccessfully).

Sources state that in 626, the crown prince Li Jiancheng and another brother, Li Yuanji the Prince of Qi, who supported Li Jiancheng, set out to ambush the rising Li Shimin. But Li Shimin heard about this trap, and organized a counter-coup, walking into the trap with several of his own most trusted and skilled soldiers. When Li Shimin mobilized his personal troops within his mansion, and as he did so, Princess Zhangsun was said to have personally made an appearance before the troops to encourage them. Her brother Zhangsun Wuji was one of Li Shimin's major strategists in this matter. Li Shimin was able to counter Li Jiancheng and Li Yuanji at Xuanwu Gate and kill them, and then essentially forced Emperor Gaozu to appoint him crown prince. Princess Zhangsun was accordingly named crown princess. Two months later, Emperor Gaozu yielded the throne to Li Shimin, who took the throne as Emperor Taizong. Princess Zhangsun, consequently, became empress, and their oldest son, Li Chengqian, became crown prince.