Li Jiancheng - Background

Background

Li Jiancheng was born in 589, during the reign of Emperor Wen of Sui. He was the oldest son of Li Yuan the Duke of Tang, a hereditary noble, and Li Yuan's wife Duchess Dou, who was herself the daughter of Dou Yi (竇毅) the Duke of Shenwu and Northern Zhou's Princess Xiangyang. Duchess Dou would subsequently give birth to three of Li Jiancheng's younger brothers -- Li Shimin, Li Xuanba (李玄霸, who died in 614), and Li Yuanji. She also gave birth to a sister of Li Jiancheng's, the eventual Princess Pingyang, although it was not clear whether she was older or younger than Li Jiancheng. At some point, Li Jiancheng received the title of Heir Apparent of Tang.

In 616, with agrarian rebellions beginning to engulf northern China and frequent Eastern Tujue incursions across the border, Emperor Yang of Sui commissioned Li Yuan to be the commander of the forces at Taiyuan, guarding it against both agrarian rebels and Eastern Tujue. At that time, Li Yuan took Li Shimin with him to Taiyuan, but left Li Jiancheng, Li Yuanji, another son Li Zhiyun (李智雲), and the rest of his household at Hedong (河東, in modern Yuncheng, Shanxi). In 617, Li Yuan, fearful that Emperor Yang might punish him for his inability to suppress the rebels led by Liu Wuzhou the Dingyang Khan, was persuaded by Li Shimin to rebel against Sui rule. He then sent secret messengers to Hedong to summon his sons and to the capital Chang'an to summon his daughter and son-in-law Chai Shao (柴紹). Li Jiancheng and Li Yuanji secretly travelled to Taiyuan, but left the 13-year-old Li Zhiyun at Hedong.