Empress Zhangsun (長孫皇后, personal name unknown) (601 – 28 July 636), formally Empress Wendeshunsheng (文德順聖皇后, literally "the civil, virtuous, serene, and holy empress") or, in short, Empress Wende (文德皇后), was an empress of the Chinese Tang Dynasty. She was the wife of Emperor Taizong and the mother of Emperor Gaozong. She was of Xianbei origin and well educated.
The future Empress Zhangsun was born in 601. Her father was the Sui Dynasty general Zhangsun Sheng (長孫晟), and her mother was Zhangsun Sheng's wife Lady Gao, the daughter of the official Gao Jingde (高敬德).She had at least four older brothers—Zhangsun Sheng's oldest son Zhangsun Xingbu (長孫行布, who was killed in 604 while resisting the rebellion of Emperor Yang of Sui's brother Yang Liang the Prince of Han), Zhangsun Heng'an (長孫恆安), Zhangsun Anye (長孫安業), and Zhangsun Wuji. (Zhangsun Wuji was also born of Lady Gao, while Zhangsun Anye was not; who Zhangsun Xingbu's and Zhangsun Heng'an's mothers were was not recorded in history.) Zhangsun Sheng died in 609, and Zhangsun Anye, instead of raising his younger brother and sister, expelled them, as well as his stepmother Lady Gao, from the Zhangsun household. He sent them back to Lady Gao's brother Gao Shilian, and Gao Shilian raised them. The future Empress Zhangsun was said to be studious and proper in her actions. In 614, she married Li Shimin, the second son of the general Li Yuan Duke of Tang. (Li Shimin was 15, and she was 13.)
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 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. 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.