There is a saying that the rescue is late, and there is another saying that the first move is strong.
The former is talking about Li Jiancheng, and the latter is li Shimin.
The Xuanwumen accident was not brewed by a day's work, but had a long history, the two groups headed by the brothers were deceitful, Li Shimin held military power, experienced hundreds of battles, and repeatedly made military achievements, and his generals were very opposed.
Li Jiancheng is not a good kind, many people think that he has done nothing, in fact, it is a big mistake, when Li Yuan attacked Chang'an City, Li Jiancheng was the first meritorious, and then destroyed Jihu, and was sent to the town to defend Puzhou, prepare for the Turks, and then capture Liu Heimin, pacify Shandong, ju meritorious to Wei, at the same time he was good at governing the government, thus winning the trust of his father Li Yuan.
The New Book of Tang Gaozu Benji contains: In July, Li Shimin, the King of Qin, asked Wang Shichong, Jia Shu, and crown prince Tun in Puzhou to prepare for the Turks.
All in all, When Li Jiancheng, the crown prince, conquered Hexi and Chang'an in the early stages, he was the first to take military merit, and at the same time he showed enough administrative ability to serve the people, so that when the world was in turmoil, he was not invaded by foreign Turks, not the nest and waste mentioned in the history books, and in recent years there have been many voices for his rehabilitation, as for the harem, it is basically equivalent to the false accusation.
During the period of the chaotic war between the world, the Turks tried to send troops to assist Liang Shidu, Liu Wuzhou and other princes, with the purpose of expanding the disorder of the Central Plains, and the powerful Turks in order to profit from it and further divide the Central Plains.
Later, Li Shimin declared war on Wang Shichong, and the Turks first sent troops to assist Wang Shichong, who had a small number of troops, and dispatched military envoys to secretly communicate and conspire with Wang Shichong, and it can be said that the most critical and urgent task in the world at that time was not to conquer Wang Shichong, but to obstruct the secret invasion of the Turks, and once the alliance with Wang Shichong was victorious, Li Tang, who was still intact in the disorder, it was difficult to distinguish the great spirit to oppose the invading Turks, so Li Jiancheng, who was in danger of giving orders and preparing for the battle in Puzhou, took on a crucial responsibility.
Thus we learn that Li Shimin led an army to conquest Wang Shichong, and Li Jiancheng was at this moment equal to the feudal governor, and his obligation was to guard the border, keep the Turks out of the way, so that they could not establish contact with the Central Plains, and restrain the Turks in order to buy more time for Li Shimin, help him defeat Wang Shichong in victory, and completely disintegrate the Turkic plot to invade the Central Plains by taking advantage of natural disasters and man-made disasters.
After that, Li Yuan ordered Li Jiancheng to conquer Jihu Lake, and Li Jiancheng took the Jihu tribe in only two months, and in April of the fourth year of Wude, Li Jiancheng withdrew from Puzhou and Banshi returned to the dynasty, so it was learned that Li Jiancheng successfully lifted the crisis of the Turks taking advantage of the opportunity.
The Old Book of Tang, vol. 64, "The Biography of the Hidden Prince", also contains: Jianchengzhi (Taiyuan), Gaozu Daxi, Baizuo general Dadu Governor, Fenglongxi County, led troops to The Western Hedu, from Pingchang'an.
It can be seen from this that Li Jiancheng was not without merit and virtue, on the contrary, his military ability made Li Yuan very happy, and the reason why Li Shimin was able to march forward in all places was not only dependent on the kings, on the contrary, Li Jiancheng's repeated cover was indispensable, it can be said that without Li Jiancheng sitting in Puzhou, blocking the turkic way into the Central Plains, cutting off the conspiracy between the Turks and Wang Shichong, Li Tang who was close to reunification would be united, thus falling into a scene of endless wars for many years.
Li Yuangui is the head of a country and the founding emperor of the Tang Dynasty, and it is not a trivial matter to establish a prince, of course, he will not choose a useless son, including the local princes and ministers of the dprk and the central government are also very supportive of Li Jiancheng, which is why he can oppose Li Shimin for a long time.
Imagine Li Shimin's conquest of the world, the unsealable military merits, if you want to force Li Yuan to abandon Li Jiancheng's crown prince, you don't have to care about the voice of opposition, you can also seize power by forcibly suppressing military power alone, why can you sit on an equal footing for such a long time, there must be too many complicated elements in this.
It is worth mentioning that Li Shimin once fought alongside his brother Li Jiancheng, and the first volume of the Tang Jian records that Gao Zu made Jiancheng and Shimin attacked Hexi County, attacked it, and took over Gao Deru.
But this is the conclusion reached by Sima Guang after examination, Li Shimin ordered the historian to write the "General Commentary" but said: "Fate Taizong Wander Hexi", Taizong refers to Tang Taizong Li Shimin, it can be seen that history was tampered with by Li Shimin, when he asked the historian to write the history book, he deliberately confessed Li Jiancheng's military merits, creating the illusion that Li Jiancheng did nothing, in order to elevate himself, or to make his brother-killing behavior become justified, but in fact, Li Jiancheng's person is not perfect, on the contrary, it is precisely because of his own military merits. As well as the opposition of the prince's regents, plus Li Yuan's covert protection, he became the crown prince.
So we can draw a conclusion that the two people continue to stop fighting each other, then the change of Xuanwumen is no longer a simple dispute to seize the wife, but can figure out more details.
First of all, Li Shimin's position when Li Tang was about to complete the unification of the world was undoubted, he was the king of Qin, but he had the right to shake Li Yuan's throne, he was experienced in hundreds of battles, he was extremely high in the army, and his merits were full of dynasties, but at that time, Li Jiancheng, as the crown prince, was opposed by the qun officials and his subordinates, and sat firmly in the position of the Eastern Palace.
It is not difficult to see from this that Li Yuan had already felt Li Shimin's ambitions, and his imperial power was fought by his son Li Shimin, so he shielded Li Jiancheng and Li Yuanji, and used their power to jointly weaken Li Shimin's Qin Wang's party power, so Li Shimin moved away from the imperial palace and retreated to the Hongyi Palace located outside the imperial city, thus completely causing The deterioration of Li Shimin's relations between Li Yuan and Li Jiancheng, and the father and son were divided into two parties, thus facing the brink of division.
And Li Yuan, as a father, was very distressed about his three sons, he never expected that the fratricidal thing would happen to his son, named Li Jiancheng as the crown prince, named Li Shimin the King of Qin, once was the expedient strategy he could think of, according to Li Yuan's original imagination, after the pacification of the world, the throne passed to Li Jiancheng, Li Shimin was stationed in the stronghold, and the Li Tang royal family sat firmly in the great cause of the country, but the illusion was finally broken in Xuanwumen.
On the eve of the xuanwumen rebellion, Li Jiancheng and Li Yuanji's conspiracy plan, the two of them planned to advise Li Yuan, requesting that Li Shimin's generals be sent to the border to oppose the Turks, so as to weaken Li Shimin's elite generals, and at the same time Li Yuanji went out on the expedition, when the brother Li Shimin must practice, although the three brothers were intolerable, but these rituals still had to be strictly observed, at this time, the two of them combined with Li Yuan to stop suppressing Li Shimin, and the imperial forces led by The Eastern Palace and Li Yuan once occupied an overwhelming advantage over Li Shimin's Qin wang party. In other words, the longer the time drags on, the more precarious Li Shimin's position becomes, and he has been at a disadvantage in this political game, so at this stressful time node, he must make a choice, or a solution.
However, the response was not Li Shimin's words, but the persuasion of his henchmen, or "persecution", and the long-term persuasion of the eldest son Wujie, Fang Xuanling and others caused Li Shimin to finally make up his mind to strike first.
The Zizhi Tongjian has a conclusive record of this matter:
The Qin officials were all worried and did not know what to do.
Fang Xuanling said that the eldest grandson had no scruples: "Now that the gap has become (alluding to the contradiction between Li Shimin and the Tang Emperor Li Yuan, and the crown prince Li Jiancheng), Mo Ruo advised the king to do the affairs of the Duke of Zhou in order to settle the country." ”
No scruples: "I have been carrying this for a long time, and I should be white." "It is the people of the world.
The people of the world summoned Xuan Ling to conspire, and Xuan Ling said: "The great king has done great things to cover the heavens and the earth, and he should inherit the great cause; today's troubles are in danger, but the heavens are praised, and may the great king not be in doubt!" ”
It was with the subordinate Du Ruyi that shimin was built and Yuan Ji was built.
The whole process is simple and direct, Fang Xuanling and the eldest son Wuji and other courtiers persuasion, on the one hand, let Li Shimin, who knows that the situation is unfavorable, make up his mind, on the other hand, unveil the last veil in front of the father and son, if you do not start first, Li Shimin is bound to fall into a fiasco after the political struggle, if it is delayed for a long time, the two sides are more likely to cause war due to the seizure of power, which will affect the stability of the entire country.
So Li Shimin planned the Xuanwu Gate accident in advance, because the Xuanwu Gate was not allowed to lead troops to enter, but the guards were accustomed to the princes carrying weapons into the palace, in other words, there was a law in front of the Xuanwu Gate, and those who entered the Imperial City could not wear weapons, but the three princes were extremely respected, carrying weapons or various objects into the palace had long been as usual, Li Shimin knew this, took the opportunity to wear weapons to enter, and was really not blocked by the forbidden army in front of the door, and because the number of his entourage was only eight, No one would think that the King of Tangtang Qin dared to lead eight people to rebel, so he was successfully released, and Li Shimin was given a heavenly opportunity to lurk in the Linhu Hall.
That night, Li Jiancheng and Li Yuanji wanted to meet Li Yuan, and proposed that Li Yuanji go out to recruit and transfer Li Shimin's generals, and when the two passed by the Linhu Hall, they did not encounter interrogation by the forbidden army who should have fulfilled their duties, so they decided that this was a precursor to the victory of Li Shimin's plan to weaken Li Shimin's power.
However, after the incident, the forbidden army has heard the shouting and killing, as for why there are no pro-soldiers to save the car, the reason is quite dramatic, just said that there are guards in front of the Xuanwu Gate, it is strictly forbidden for individuals to carry weapons inside, when the palace guards learned that Jiancheng and Yuanji were killed, they immediately went to report the news, the palace soldiers immediately gathered a large group of people and horses, wanted to rush into the imperial city to save the car, but the defenders saw Li Shimin nine people before they were not stopped, one is because of the small number of people, the second is because of Li Shimin's status as a prince, the prince took eight people to tour the imperial city at night, to put it mildly, It was like drinking too much wine in the middle of the night and going home to sleep, but there were thousands of soldiers in the palace, and the forbidden army that guarded the city saw this battle, and immediately faced a great enemy and strictly obstructed it.
At the same time, the news of the killing of the crown prince and Li Yuanji, the king of Qi, spread throughout the imperial city, and the defenders of the city naturally knew about it, but Li Shimin sent another person to make a promise with the defending soldiers, secretly cooperating with Li Shimin, desperately blocking the entry of the palace army, and on the other side, the qin prince army that had been prepared also came to escort Li Shimin, which was the internal and external cooperation, and successfully launched the Xuanwumen Revolution.
The Old Book of Tang and the Biography of Wei Chi Jingde have a detailed account of the process:
On June 4, jiancheng died, Jingde led seventy horses to heels, Yuan Ji walked east, shooting left and right to fall off the horse. Emperor Taizong's horse was wandering under the forest, and he was swept away and could not be happy when he fell. Yuan Ji came to grab the bow, and he wanted to strangle him, and Jingde Prancing Horse Lingzhi, so he walked away, wanting to return to the Wude Hall, and Jingde Ben shot it one by one.
Soon, Li Yuan was forced to declare Li Shimin the Prince of Qin crown prince.
Li Shimin succeeded to the throne as Emperor Taizong of Tang and was given the era name Zhenguan.