Li Jiancheng [SEP] sister
Prefecture (魏州, in modern Handan, Hebei), Li Jiancheng and Li Yuanji engaged him at Guantao (館陶, in modern Handan as well), crushing him. Liu fled north toward Eastern Tujue, but was ambushed and captured by his own official Zhuge Dewei (諸葛德威), who delivered him to Li Jiancheng. Li Jiancheng executed Liu. China was by this point almost completely unified by Tang.
In 623, when Eastern Tujue made another incursion into Tang territory,Li Yuan again sent Li Jiancheng and Li
, 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. He had three older brothers by Duchess Dou -- Li Jiancheng, Li Shimin, and Li Xuanba (李玄霸, who died in 614). She also gave birth to an older sister of Li Yuanji's, the eventual Princess Pingyang.
In 616, with agrarian rebellions beginning to engulf northern China and frequent Eastern Tujue incursions across the border