Princess Pingyang

The future Princess Pingyang was the third daughter of Li Yuan, then Duke of Tang, a hereditary nobleman of Sui China and cousin of Emperor Yang. She was his third daughter, but the only daughter of his wife Duchess Dou, who also bore four sons, Li Jiancheng, Li Shimin (later Emperor Taizong), Li Xuanba, and Li Yuanji. Eventually, Li Yuan gave her in marriage to Chai Shao, the son of Chai Shen (柴慎) the Duke of Julu.

She is not to be confused with another Princess Pingyang from the Western Han dynasty.

In 617, Li Yuan, then the general in charge at Taiyuan was planning to rebel against Emperor Yang of Sui, by whom he had been imprisoned before. He sent messengers to his daughter and son-in-law Chai Shao, then at the Sui capital Chang'an, summoning them back to Taiyuan. Chai worried that they would not be able to escape together easily, and when he consulted her, she told him to go and that she, as a woman, would be able to hide more easily. He therefore secretly headed for Taiyuan and, after first meeting Li Jiancheng and Li Yuanji, whom Li Yuan had similarly recalled from Hedong (河東, now part of Yuncheng, Shanxi), reported to Taiyuan.

Pingyang hid initially, but then distributed her wealth to several hundred men, receiving their loyalty, so she rose in support of Li Yuan. She sent her servant Ma Sanbao (馬三寶) to persuade the agricultural rebel leader He Panren (何潘仁) to join her, and then also persuaded other rebel leaders Li Zhongwen (李仲文), Xiang Shanzhi (向善志), and Qiu Shili (丘師利) to join her as well. She attacked and captured some of the nearby cities and garrisons, and she gathered a total of 70,000 men.

Late in 617, Li Yuan crossed the Yellow River into the Chang'an region and sent Chai Shao to rendezvous with her. They then joined Li Shimin, commanding one wing of Li Yuan's army. Chai and she set up separate headquarters as commanding generals, and her army became known as the "Army of the Lady." In June 618, Li Yuan had Emperor Yang's grandson Yang You yield the throne to him, establishing the Tang dynasty as Emperor Gaozu. He created her the Princess Pingyang, and as she contributed greatly to his victory, he particularly honored her over his 18 other daughters.

Princess Pingyang, however, was not recorded as having been involved in another battle after her father's capture of Chang'an; she later died in March 623. While historians do not know the true cause of her death, one popular theory is that she died from childbirth, during the birth of her second son. An alternative theory is that she died from battle wounds which later caused health implications. There is speculation of various other causes including assassination from her brothers and sacrifice during battle. However, these seem improbable, especially considering there were no records of her fighting after Chang’an. At her funeral on 18 March 623, Emperor Gaozu ordered that a grand military funeral, fit for a high general, be given for her. When officials of the Ministry of Rites objected to the presence of a band, stating that women's funerals were not supposed to have bands, he responded, "As you know, the princess mustered an army that helped us overthrow the Sui dynasty. She participated in many battles, and her help was decisive in founding the Tang dynasty. ... She was no ordinary woman." The band did indeed play, thus making her the only woman in imperial Chinese history to be honored with a military funeral. After she passed, Niangzi Pass was named in her honor (also known as Lady's Pass, or Young Lady's Pass).

Princess Pingyang and her husband, Chai Shao, had two sons:

• Chai Zhewei 柴哲威, titled Duke of Qiao
• Chai Lingwu 柴令武 (died 653), titled Duke of Xiangyang Commandery (襄阳郡公), married Emperor Taizong's daughter Princess Baling (巴陵公主)