In history, Cao Cao's relocation of the capital to Xuchang and the control of the Son of Heaven was the most important turning point in the development of the entire Cao Cao Group, and the influence of the Son of Heaven on the future development of the Cao Cao Group can be said to be incomparable, directly changing the future of the Cao Cao Group.

As for how important it is, it can be seen by comparing Cao Cao's performance before and after welcoming the Son of Heaven.

Cao Cao was elected as the pastor of Yanzhou in the third year of Chuping (192), sent Cao Hong to welcome the Son of Heaven for the first time in the first year of Jian'an (196), moved the capital to Xuchang in the second half of the year, and was already preparing for a decisive battle with Yuan Shao in the fourth year of Jian'an (199). Therefore, we take the early years of Jian'an as the boundary, and compare the development and achievements of Cao Cao's group in the first four years (from the third year of Chuping to the second year of Xingping, that is, 192-195) and the last four years (from the first year of Jian'an to the fourth year of Jian'an, that is, 196-199), and see how important the Son of Heaven was to Cao Cao and Cao Cao's group.

The first four years of Jian'an were the first period of development of Cao Cao Group. During this period, Cao Cao had just become the pastor of Yanzhou, and faced many internal and external challenges, mainly to stabilize his territory.

In the third year of Chuping (192), Liu Dai, the former assassin of Yanzhou, was killed in battle, and Cao Cao was elected as the pastor of Yanzhou by everyone at the suggestion of Chen Gong. After Cao Cao became the pastor of Yanzhou, he began to vigorously clean up the Yellow Turban thieves in Yanzhou, and received more than 300,000 soldiers.

From the end of the year to the beginning of the following year, Cao Cao and Yuan Shao formed an alliance to jointly resist the crusade of Yuan Shu, Gongsun Zan and Tao Qian's combined army, and the Yuan Cao coalition army first repelled the armies of Liu Bei, Shan Jing and Tao Qian under Gongsun Zhan, and then in the Yanzhou War, the combined forces of Yuan Shu, Jin Shang and the Xiongnu Yu Fuluo and the Black Mountain Thieves were defeated, and Yuan Shu was driven to Yangzhou.

In the second half of the fourth year of Chuping (193), Cao Cao's father Cao Song and younger brother Cao De were killed by the people of Xuzhou, Cao Cao avenged his father, invaded Xuzhou on a large scale, and the blood flowed like a river everywhere he passed, Tao Qian could barely resist it, and was forced to ask for help from Tian Kai, the assassin of Qingzhou, when Tian Kai and Liu Bei came to help, it happened that Cao Cao's army was exhausted and retreated, and the first battle of Xuzhou ended hastily.

At the beginning of the following year, Cao Cao invaded Xuzhou again after being ready, another massacre, and Liu Bei and Cao Bao, whom Tao Qian hoped for, were not Cao Cao's opponents at all, and when Tao Qian was almost desperate, Cao Cao was forced to withdraw his troops due to problems in Yanzhou, Cao Cao's rear, and Xuzhou was saved.

In the first year of Xingping (194), Zhang Miao, Chen Gong and others took advantage of Cao Cao's crusade against Xuzhou to betray Cao Cao to welcome Lü Bu into Yanzhou, Cao Cao waved his army to turn around and start a war with Lü Bu, the two sides first fought in Puyang for a hundred days, basically no one up and down, and then the two sides had to strike because of the locust plague and grain and grass problems, and then after the war, Cao Cao stood on the upper hand, several battles, and finally drove Lü Bu out of Yanzhou in the following year.

In the second year of Xingping (195), Cao Cao sent an envoy to the imperial court and was officially appointed as the pastor of Yanzhou by Emperor Xian of the Han Dynasty.

In the first four years, Cao Cao successively pacified the Yellow Turban Thieves, repelled the invasion of Yuan Shu, crusaded against Xuzhou twice, and drove away Lu Bu in Yanzhou, which can be said to be a brilliant record.

In the last four years of Jian'an, it was a period of rapid development of Cao Cao's group, Cao Cao with the help of the righteous name of the Son of Heaven, the power of Yanzhou rapidly expanded from Yanzhou to Yuzhou, Sili, Xuzhou, Jingzhou, Yangzhou, Qingzhou several large states, which completely controlled Yanzhou, Yuzhou, Xuzhou, and got a part of Sili, Yangzhou, Jingzhou, and Qingzhou.

In the first year of Jian'an (196), Cao Cao once sent Cao Hong to welcome the Son of Heaven, but was finally blocked by Dong Cheng and others, and then Cao Cao personally went to Chang'an, and quickly moved the capital to Xuchang, successfully controlled the imperial court, and achieved the name of righteousness.

In the same year, Cao Cao marched into Yuzhou, and Yuan Shu's appointed Chen Xiang Yuan Si surrendered, and basically wiped out the Yellow Turban Army in Yuzhou that had submitted to Yuan Shu, and the rest of the party also surrendered to Cao Cao. Later, Cao Cao took the opportunity to defeat Yang Feng and Han Xian in Liangdi, and the two later took refuge in Yuan Shu, and after Liu Bei returned to Shun, he was appointed by Cao Cao as the pastor of Yuzhou. Yuzhou was initially pacified by Cao Cao.

At the beginning of the second year of Jian'an (197), Cao Cao crusaded against Zhang Xiu in Nanyang, Zhang Xiu first surrendered without a fight, but then suddenly rebelled, Cao Cao was caught off guard and was defeated, and his eldest son Cao Ang, Ai General Dian Wei, Ai Ma Jueying, and nephew Cao Anmin were all killed in this battle.

In the same year, Yuan Shu proclaimed himself emperor, and invaded Chen in the second half of the year, Cao Cao personally led the army to crusade, won a complete victory, and killed Yuan Shu's generals Qiao Rui, Li Feng, Liang Gang, and Le Zhuo, and Yuan Shu retreated to Huainan. Yuzhou was basically pacified by Cao Cao.

In the same year, Cao Cao sent Cao Hong to crusade against Zhang Xiu, which was unfavorable, and then personally led the army to crusade against Nanyang for the second time, conquering Huyang and Wuyin.

At the beginning of the third year of Jian'an (198), Cao Cao led his army to crusade against Zhang Xiu for the third time, but still did not achieve victory, due to the news that Yuan Shao might march to Xuchang, Cao Cao withdrew first.

In the same year, Lü Bu betrayed the imperial court, reunited with Yuan Shu, and sent Gao Shun to defeat Liu Bei and Xiahoudun, who went to the rescue. So Cao Cao decided to march into Xuzhou and eliminate Lü Bu.

In this battle of Xuzhou, Cao Cao first slaughtered Pengcheng, broke Lü Bu's army several times under Xiapi City, and finally surrounded Lü Bu in Xiapi, and after the rebellion left, Lü Bu surrendered to Cao Cao and was killed. After Lü Bu was eliminated, Xuzhou was initially pacified by Cao Cao.

At the beginning of the fourth year of Jian'an (199), Zhang Yang, the Taishou of Hanoi, was killed by the general Yang Chou, and Yang Chou was killed by Zheng Gu, who was ready to take refuge in Yuan Shao, so Cao Cao sent Shi Jian and Cao Ren to cross the river to attack it, and broke his army, and Cao Cao's sphere of influence also expanded to the north of the Yellow River for the first time.

In the second half of the same year, Cao Cao sent Zang Ba to march into Qingzhou and control Beihai, Dong'an and other places. Cao Cao's sphere of influence reached Qingzhou.

At the end of the year, Zhang Xiu surrendered to Cao Cao again at Jia Xu's suggestion, and was appointed by Cao Cao as a liehou, so Cao Cao received Nanyang County in Jingzhou.

In the same year, Cao Cao appointed Yan Xiang Yangzhou to assassinate the history, and united other princes to crusade against Yuan Shu, after Yuan Shu was destroyed, Cao Cao got the Huainan area of Yangzhou.

The first four years and the last four years of Cao Cao are brilliant achievements, but the achievements are thousands of miles apart, of course, the middle is not only the reason for Emperor Han Xian alone, but from which we can also see how important the righteousness of the Son of Heaven is to Cao Cao, Cao Cao without the Son of Heaven has been only the lord of Yanzhou at most for four years, but Cao Mengde, who controls the imperial court, has begun to get involved in the world in four years, and has become one of the two men who are closest to the final victory at that time.

Of course, controlling the Son of Heaven will also bring certain drawbacks, but compared with the benefits it brings, how to choose is really not in words.

It is not an exaggeration to say that "coercing the Son of Heaven and ordering the princes" was a turning point in the fate of Cao Cao and his group.

PS: This article gives you a preliminary understanding of the importance of the "righteousness of the Son of Heaven" through a simple direct comparison, and there will be a further description of this aspect later. This chapter is the last chapter of the third volume, and the next volume is the fourth volume, The Rise and Fall of the Yuan Clan.