Li Jiancheng (李建成) (589 – July 2, 626), formally Crown Prince Yin (隱太子, literally, "the hidden crown prince"), nickname Pishamen (毗沙門), was a crown prince of the Chinese dynasty Tang Dynasty. He was the oldest son of the founding emperor Emperor Gaozu (Li Yuan) and therefore was designated crown prince after the founding of the dynasty in 618. However, although he himself was fairly capable as a general, he was overshadowed by the contributions of his younger brother Li Shimin the Prince of Qin, and the brothers contended for power for years, with Li Jiancheng aided by another younger brother, Li Yuanji the Prince of Qi. In 626, Li Shimin, fearing that Li Jiancheng and Li Yuanji were about to kill him, laid an ambush for them at Xuanwu Gate outside the palace and killed them. Li Shimin then effectively forced Emperor Gaozu to yield the throne to him (as Emperor Taizong).
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.
Participation in Tang's founding
Even before Li Jiancheng, Li Yuanji, and Chai Shao (who, at the urging of Li Yuan's daughter, left Chang'an on his own while she went into hiding) arrived at Taiyuan, Li Yuan rebelled, declaring that he wanted to support Emperor Yang's grandson Yang You the Prince of Dai, then nominally in charge at Chang'an, as emperor, while honoring Emperor Yang as Taishang Huang (retired emperor). In response, Sui officials arrested Li Zhiyun, took him to Chang'an, and executed him.
Li Yuan made both Li Jiancheng and Li Shimin key generals, and in nine days, they captured Xihe Commandery (西河, roughly modern Lüliang, Shanxi), impressing their father. Subsequently, Li Yuan divided his forces into six armies, having Li Jiancheng and Li Shimin command three each. He also created Li Jiancheng the Duke of Longxi and Li Shimin the Duke of Dunhuang. Subsequently, Li Yuan advanced toward Chang'an, but when he got near to Hedong, his army could not advance due to torrential rains. With rumors running rampant that Liu Wuzhou and Eastern Tujue were about to attack Taiyuan, Li Yuan began ordering a retreat back to Taiyuan; it was only at Li Jiancheng's and Li Shimin's urging (that retreating back to Taiyuan would mean sure defeat) that Li Yuan changed his mind and stayed, and Li Jiancheng and Li Shimin then captured the fortress of Huoyi (霍邑, in modern Linfen, Shanxi), eventually convincing Li Yuan to bypass Hedong and directly advance toward Chang'an. After he crossed the Yellow River into Guanzhong (i.e., the Chang'an region), he sent Li Jiancheng with Liu Wenjing (劉文靜) east to guard Tong Pass and Yongfeng Storage (永豐倉) and to stop any potential Sui reinforcements from the eastern capital Luoyang. Once Li Yuan himself approached Chang'an, he summoned both Li Jiancheng and Li Shimin (whom he had sent north of the Wei River to seize territory) to Chang'an to join him in sieging Chang'an. In winter 617, Li Yuan captured Chang'an and declared Yang You emperor (as Emperor Gong). He had himself created the Prince of Tang, become the regent over Emperor Gong.
In spring 618, Li Yuan sent Li Jiancheng and Li Shimin toward Luoyang, which was then under attack by the rebel leader Li Mi the Duke of Wei, ostensibly to help Sui forces there. The Sui forces at Luoyang rejected the overture, and Li Jiancheng and Li Shimin subsequently returned to Chang'an.
Later in spring 618, Emperor Yang, then at Jiangdu (江都, in modern Yangzhou, Jiangsu), was killed in a coup led by the general Yuwen Huaji. When the news arrived at Chang'an, Li Yuan had Emperor Gong yield the throne to him, establishing Tang Dynasty as its Emperor Gaozu. Emperor Gaozu created Li Jiancheng crown prince.
In 619, Emperor Gaozu sent Li Jiancheng to attack the agrarian leader Zhu Shanhai (祝山海) the Duke of Huxiang, and Li Jiancheng defeated Zhu. Later that year, when Li Gui the Emperor of Liang was captured in a coup by his official An Xinggui (安興貴), who then submitted to Tang, Emperor Gaozu sent Li Jiancheng to welcome An and to escort Li Gui to Chang'an, where Emperor Gaozu executed him.
Meanwhile, Li Jiancheng was developing a reputation for leniency but favoring drinking and hunting. Emperor Gaozu, worried that he was not paying sufficient attention to the important matters of state, had the key ministers Li Gang (李綱) and Zheng Shanguo (鄭善果) join Li Jiancheng's staff.
In fall 620, believing in reports that Li Zhongwen (李仲文), who was then in charge at Taiyuan, was collaborating with Eastern Tujue, was planning to rebel, Emperor Gaozu sent Li Jiancheng to Pufan (蒲反, i.e., Hedong) to guard against Li Zhongwen, while summoning Li Zhongwen back to the capital. Li Zhongwen complied and was subsequently executed.
In spring 621, when the Xiongnu chieftain Liu Xiancheng (劉仚成) harassed Tang's border territory, Emperor Gaozu sent Li Jiancheng to attack Liu. When Li Jiancheng subsequently captured a number of the Xiongnu, he initially released their leaders, leading them to surrender in large numbers, and he then massacred them. Only Liu escaped and fled to Liang Shidu the Emperor of Liang. In 622, Li Jiancheng was one of the commanders that Emperor Gaozu sent, along with Li Shimin, Li Zihe (李子和), and Duan Decao (段德操), to counter an Eastern Tujue incursion.
Rivalry with Li Shimin
Meanwhile, an intense rivalry had developed between Li Jiancheng and Li Shimin, who carried the title of Prince of Qin, as while Li Jiancheng had some contributions toward Tang's reunification of China, a number of the more major contenders, including Xue Rengao the Emperor of Qin, Wang Shichong the Emperor of Zheng, and Dou Jiande the Prince of Xia, were all defeated and/or captured by Li Shimin, causing him to possess the greater reputation among the army. Li Yuanji, who was also often relied on by Emperor Gaozu as a general and had been created the Prince of Qi, supported Li Jiancheng in this rivalry, and often pushed Li Jiancheng toward a more hardline position against Li Shimin, wanting to be crown prince when Li Jiancheng would become emperor. Li Jiancheng and Li Yuanji had better relations with Emperor Gaozu's favored young concubines than Li Shimin did (as their mother Duchess Dou had died before Tang's establishment), and those concubines helped rehabilitate Li Jiancheng's standing before Emperor Gaozu, causing him to no longer consider making Li Shimin crown prince instead, as he considered at one point.
By winter 622, Liu Heita the Prince of Handong, previously a Xia general who rose against Tang after Emperor Gaozu had executed Dou Jiande, posed the only remaining major threat against Tang rule even though he had been defeated by Li Shimin earlier in the year. At the suggestion of his staff members Wang Gui and Wei Zheng, who argued that Li Jiancheng needed some victories himself to establish his reputation, Li Jiancheng volunteered to command the army against Liu Heita. Emperor Gaozu thus sent Li Jiancheng, assisted by Li Yuanji. Around the new year 623, with Liu's forced bogged down while attacking Tang's Wei 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, Emperor Gaozu again sent Li Jiancheng and Li Shimin to guard against the attack. Meanwhile, at one point, Li Yuanji tried to persuade Li Jiancheng to have Li Shimin assassinated when Li Shimin was visiting Li Yuanji's mansion, but Li Jiancheng, not having the heart to kill a brother, stopped Li Yuanji from doing so.
In 624, Li Jiancheng requisitioned a number of soldiers from the general Li Yi the Prince of Yan, to supplement his guard corps, against Emperor Gaozu's regulations. When this was revealed to Emperor Gaozu, Emperor Gaozu rebuked Li Jiancheng and exiled his guard commander Keda Zhi (可達志). When, subsequently, Li Jiancheng nevertheless requested the commandant at Qing Prefecture (慶州, in modern Qingyang, Gansu), Yang Wen'gan (楊文幹), to conscript troops, presumably to guard against Li Shimin, the officers Erzhu Huan (爾朱煥) and Qiao Gongshan (橋公山) informed Emperor Gaozu that Li Jiancheng was encouraging Yang to start a rebellion so that they could seize power together. Emperor Gaozu, then at Renzhi Palace (仁智宮, in modern Tongchuan, Shaanxi), was incensed, and summoned Li Jiancheng, then at Chang'an, to Renzhi Palace. Li Jiancheng briefly flirted the idea of occupying Chang'an and not accepting the order, but eventually reported to Renzhi Palace to request forgiveness. Emperor Gaozu put him under arrest. When Yang heard this, Yang rebelled, and Emperor Gaozu, after promising Li Shimin that he would be made crown prince, sent Li Shimin to attack Yang. (Under Emperor Gaozu's promise, Li Jiancheng would be removed as crown prince and created the Prince of Shu instead. He would then send Li Jiancheng to the modern Sichuan region.) Once Li Shimin left, however, Li Yuanji, Emperor Gaozu's concubines, and the chancellor Feng Deyi, all spoke on Li Jiancheng's behalf, and Emperor Gaozu changed his mind, released Li Jiancheng, and allowed him to return to Chang'an and remain as crown prince. Instead, Emperor Gaozu only blamed the discord between his sons on Li Jiancheng's staff members Wang Gui and Wei Ting (韋挺), and Li Shimin's staff member Du Yan, exiling them. Yang was subsequently assassinated by his own subordinates.
Later that year, Emperor Gaozu, troubled by repeated Eastern Tujue incursions, seriously considered burning Chang'an to the ground and moving the capital to Fancheng, a suggestion that Li Jiancheng, Li Yuanji, and the chancellor Pei Ji agreed with. Li Shimin opposed, however, and the plan was not carried out. Meanwhile, Li Shimin himself was sending his confidants to Luoyang to build up personal control of the army there. After an incident in which Li Shimin suffered a severe case of food poisoning after feasting at Li Jiancheng's palace -- an event that both Emperor Gaozu and Li Shimin apparently interpreted as an assassination attempt -- Emperor Gaozu considered sending Li Shimin to guard Luoyang to prevent further conflict, but Li Jiancheng and Li Yuanji, after consulting each other, believed that this would only give Li Shimin an opportunity to build up his personal power there, and therefore opposed it. Emperor Gaozu therefore did not carry out the plan.
By 626, Li Shimin was fearful that he would be killed by Li Jiancheng, and his staff members Fang Xuanling, Du Ruhui, and Zhangsun Wuji were repeatedly encouraging Li Shimin to attack Li Jiancheng and Li Yuanji first -- while Wei Zheng was encouraging Li Jiancheng to attack Li Shimin first. Li Jiancheng persuaded Emperor Gaozu to remove Fang and Du, as well as Li Shimin's trusted guard officers Yuchi Jingde and Cheng Zhijie (程知節), from Li Shimin's staff. Zhangsun, who remained on Li Shimin's staff, continued to try to persuade Li Shimin to attack first.
In summer 626, Eastern Tujue was making another attack, and under Li Jiancheng's suggestion, Emperor Gaozu, instead of sending Li Shimin to resist Eastern Tujue as he first was inclined, decided to send Li Yuanji instead. Li Yuanji was given command of much of the army previously under Li Shimin's control, further troubling Li Shimin, who believed that with the army in Li Yuanji's hands, he would be unable to resist an attack. Li Shimin had Yuchi summon Fang and Du back to his mansion secretly, and then on one night submitted an accusation to Emperor Gaozu that Li Jiancheng and Li Yuanji were committing adultery with Emperor Gaozu's concubines. Emperor Gaozu, in response, issued summonses to Li Jiancheng and Li Yuanji for the next morning, convening the senior officials Pei Ji, Xiao Yu, and Chen Shuda to examine Li Shimin's accusations. As Li Jiancheng and Li Yuanji approached the central gate leading to Emperor Gaozu's palace, Xuanwu Gate (玄武門), Li Shimin carried out the ambush he had set. He personally fired an arrow that killed Li Jiancheng. Subsequently, Yuchi killed Li Yuanji. Li Shimin's forces entered the palace and, under the intimidation of Li Shimin's forces, Emperor Gaozu agreed to create Li Shimin crown prince, and two months later passed the throne to him (as Emperor Taizong). Li Jiancheng's five sons were all executed as well.
Li Jiancheng was initially posthumously reduced to commoner rank. After Emperor Taizong took the throne, he posthumously created Li Jiancheng the Prince of Xi and adopted his own son Li Fu (李福) into Li Jiancheng's line as Li Jiancheng's heir. He also buried Li Jiancheng with ceremonies due an imperial prince. In 642, he restored Li Jiancheng's crown prince title. However, for political considerations, he would never have Li Jiancheng fully rehabilitated, as the daughters of Li Jiancheng still remained the titles as daughters of a common prince, rather than a crown prince.