During the Three Kingdoms period, "holding the Son of Heaven to order the princes" was not the first creation of Cao Cao, in fact, Dong Zhuo was the one who first played this set, but Dong Zhuo could not play it, and finally played himself to death. Not only did it fail to command the princes, but it attracted the crusade of the princes. However, after that, it was not only Cao Cao who had such an opportunity, but every prince had such an opportunity, especially Yuan Shao and Yuan Shu's brothers, who were strong in strength and had greater opportunities than others.
However, they could not see the benefits that could be brought by having the sign of Emperor Xian of Han, especially Yuan Shu, in his mind, the stone of "Jade Seal" was obviously much more useful than the living sign of Emperor Xiandi of Han. Only Cao Cao saw the opportunity and held Tianzi hostage. If Cao Cao hadn't done this, what would he have been mixed up like? Can the North still be unified?
Before discussing this question, we can first look at how much benefit "holding the Son of Heaven to order the princes" has brought to Cao Cao.
First, recruit talents. As early as when Cao Cao occupied Yanzhou, Mao Jiu constantly suggested to Cao Cao that "it is advisable to serve the Son of Heaven so that he should not be subordinated", and Cao Cao agreed with this suggestion very much, so after having the sign of Emperor Xian of Han, it played an unimaginable role in Recruiting talents for Cao Cao. Take Xun Yu, for example, who defected to Yuan Shao before, and then left for Cao Cao's side. Although the historical records do not clearly indicate the specific reasons for Xun Yu's defection to Cao Cao. However, from the later Xun Yu's opposition to Cao Cao and the King of Wei jia jiuxi, we can see that Xun Yu joined the root because of the Han plot.
Xun Yu was loyal to the Han dynasty all his life, so he would oppose Cao Cao's disobedience, and it was precisely because Cao Cao welcomed The Emperor of Han earlier that Xun Yu worked for Cao Cao, and also recommended a large number of talents for him, such as Chen Qun, Guo Jia, Zhong Xuan and a large number of top talents. And these talents were later core members of Cao Cao. Therefore, it was precisely because Cao Cao welcomed Emperor Xian of Han to obtain an orthodox legal status that he attracted a large number of talents to join and helpEd Cao Cao achieve great things.
Second, partial unification. As mentioned earlier, it is precisely because Cao Cao has the sign of "holding the son of heaven", so there are a large number of high-end talents to join. But in addition, another benefit was to help Cao Cao unify the north. Take the Battle of Guandu, for example, its victory is also due to the "holding the Son of Heaven to order the princes", on the eve of the Battle of Guandu, Yuan Shao sent people to contact Zhang Xiu many times to fight against Cao Cao in order to defeat Cao Cao, but Zhang Xiu had concerns and did not dare to agree, and the fundamental reason was that "Fu Cao Gong obeyed the Son of Heaven to order the world not to submit to the world". Later, Zhang Xiu's surrender allowed Cao Cao to deal with Yuan Shao wholeheartedly and have no worries anymore.
In addition, including when Cao Cao later attacked Jingzhou, Liu Chun surrendered because of this. Therefore, it is enough to see how much the chip of "holding the Son of Heaven" played a big role at that time! In other words, if Cao Cao did not have the chip of Emperor Xian of Han, not only would he not have so many top talents under his account, but I am afraid that even unifying the north would be a difficult task, let alone in the future.