Fang Xuanling, as a strategist of Li Shimin's concubine, has been following Li Shimin and is the main planner of the change of Xuanwumen, Zhenguan became the prime minister for three years, until Zhenguan died in the twenty-second year, becoming a veritable political tumbler in the Tang Dynasty, and Fang Moududu also became the best good partner in later generations. So why was Fang Xuanling able to create such a miracle?

First, Fang Xuanling is very capable and cautious. The New Book of Tang commented that Fang Xuanling had been in power for twenty years, had been diligent and strong at night, and had exhausted the festival of ren gong, not letting a talent be buried, and not letting a mediocre talent get away with it. Don't be jealous of your ability, and hear that others have strengths as if you had strengths in yourself. Officials are skillful, and they must seek fairness in their affairs, and do not demand from others without their own merits, and do not blame others for their perfection. If something is wrong and is criticized by Li Shimin, he will definitely kowtow and plead guilty, like walking on thin ice, and regard it as intolerable. In his later years, Li Shimin was jealous of the heroes, led an expedition to Goguryeo, Fang Xuanling stayed behind to assist the crown prince, and within two days a person found Fang Xuanling and told him to rebel in person, Fang Xuanling did not say a word to escort this person and the informant materials to Li Shimin, Li Shimin beheaded this person on the spot, and said to Fang Xuanling, I absolutely trust you, you don't have doubts. In fact, if anyone sues people in person, they are not afraid to extinguish their mouths. It can be seen that this person is Li Shimin who arranged to test Fang Xuanling, one handled carelessly and his old life was difficult to protect, Fang Xuanling passed the pass safely, and the other prime minister Liu Bo became a ghost under the knife. That's the gap.
Second, Li Shimin has a good hand under the emperor and a skill in employing people. In the late Tang Dynasty, Prime Ministers Li Deyu and Tang Wuzong said that during the Kaiyuan Period, the Prime Ministers worked for up to three years at a time, and Yao Chongsong Jing was no exception. Later, Li Linfu worked for nineteen years, which led to the Anshi Rebellion. Some people objected, saying that you are blind, and you did not see that Fang Xuanling worked for twenty years during the Zhenguan period, and Wei Zheng worked for fifteen years until he died. In fact, this is sophistry. Managing and employing people is a technical job, if the emperor has Li Shimin's wise decision, it can be, if not, there will be chaos. A prime minister has been a prime minister for a long time, and his protégés and former officials are all over the government and the public, and if they form a party for personal gain, they will pose a threat to the imperial power. Cao Cao Zhuge Liang is a clear example. Therefore, Fang Xuanling can be twenty years, which is a good story of meeting Li Shimin, who is a wise lord and hero, and changing some people may not be able to create a junming chenxian. The later eldest grandson was unlucky.
Third, the empress dowager was entrusted on her deathbed. Fang Xuanling was also sent back to his hometown by Li Shimin for making a mistake and prepared to abandon it. Empress Zhenguan's eldest grandson was critically ill, and on his deathbed he told Li Shimin that Fang Xuanling had followed you for so many years, careful and careful, scheming and secretive, and had not tried to vent, if he had not made any big mistakes, I hope you will never abandon him. Li Shimin shook his wife's hand and tearfully agreed. Since then, fang Xuanling has no longer been harsh, even if he is sometimes dissatisfied, remembering his wife's dying instructions, he has maintained tolerance for him, and at most he is angry and scolded twice. Therefore, Fang Xuanling could be the prime minister for twenty years until he died. In the later period of Zhenguan, Li Shimin was resolute and decisive, and his suspicions were deep, Fang Xuanling's long palm center was able to die well, and the eldest grandson empress was very successful.