In the second year of Jian'an (197), after Yuan Shu became emperor, two imperial courts briefly appeared in the Central Plains Continent.

When Yuan Shu first became emperor, in fact, Cao Cao did not immediately crusade against Yuan Shu, and the reason why Cao Cao later went to crusade against Yuan Shu was because Yuan Shu tried to recapture Yuzhou, but in fact, Yuan Shu made the first move.

Originally, Yuzhou was generally Yuan Shu's sphere of influence, but after Cao Cao forced Yuan Shu to surrender Yuan Xiang's heir, and almost recovered and annihilated the Yellow Turban Army loyal to Yuan Shu in the Yuzhou area, and appointed Liu Bei, who was at odds with Yuan Shu and Lu Bu, as the pastor of Yuzhou, Yuzhou basically became Cao Cao's sphere of influence.

After Yuan Shu failed in the crusade against Lü Bu, he turned his target to Yuzhou, and personally led the army to capture the Chen State in Yuzhou, after Cao Cao learned the news, he immediately turned to march into Yuzhou to defeat Yuan Shu, and finally Yuan Shu fled back to Huainan, but several generals under his command were killed by Cao Cao, and he couldn't afford to fall from then on.

After Yuan Shu became emperor, Cao Cao, as a representative of the imperial court, did not attach much importance to Yuan Shu, and there were many reasons for this.

First of all, Cao Cao was busy. You know, when Yuan Shu called the emperor was the second year of Jian'an (197), and at that time the first battle of Wancheng had just ended, Wancheng was Cao Cao's sad place, after Zhang Xiu and Liu Biao reunited, the threat to Xuchang was close at hand, if it was not for Yuan Shu's invasion of Yuzhou in history, Cao Cao might not have the kung fu to deal with Yuan Shu.

And Cao Cao defeated Yuan Shu's army in Yuzhou, and even beheaded Qiao Rui, Li Feng, Liang Gang, and Le on four generals under Yuan Shu, it can be said that if Cao Cao directly entered Huainan at that time, it was likely to end Yuan Shu, but Cao Cao did not continue to pursue Yuan Shu, why?

Or because there was a problem in Nanyang, after Cao Cao Wancheng failed to return to Xuchang, many counties in Nanyang County rebelled and took refuge in Zhang Xiu, Cao Cao sent Cao Hong to quell the rebellion because he wanted to deal with Yuan Shu, but Cao Hong was not Zhang Xiu's opponent, so he was defeated, and Cao Cao could only give up the pursuit of Yuan Shu and come back to prepare to clean up Zhang Xiu.

Secondly, the reason for the journey. Yuan Shu's base camp Huainan is far away from Cao Cao's hometown Xuchang, and Cao Cao's crusade against Yuan Shu takes a lot of time and energy, and the gains outweigh the losses.

Of course, after Yuan Shu became emperor, the reason why Cao Cao didn't take it too seriously was also related to Cao Cao's surrounding environment, and Yuan Shu's threat to Cao Cao was not much.

If from the perspective of the central court and from the perspective of the Son of Heaven, Yuan Shu called the emperor the founding of the country, which is completely intolerable and needs to be eliminated as soon as possible, but if it is from Cao Cao's point of view, it is another matter.

At that time, Cao Cao had many enemies around him, and they were much more threatening than Yuan Shu.

First of all, Zhang Xiu, who is three steps away, why did Cao Cao crusade against Zhang Xiu and control Nanyang County in history, is it because Nanyang and Xuchang are too close, so close that Cao Cao can't bear it.

But Nanyang County is the gateway to Jingzhou, and Zhang Xiu is also attached to Liu Biao, so it is impossible for Liu Biao to watch Cao Cao eliminate Zhang Xiu, so Cao Cao's handling of Zhang Xiu is equivalent to dealing with Zhang Xiu and Liu Biao, which is also one of the most important reasons why Cao Cao's four crusades against Zhang Xiu were ultimately unsuccessful.

Cao Cao spent more than a year on Nanyang's side, and in the end he basically returned in vain, how do you say that he has time to pay attention to Yuan Shu, who is a hundred and eight miles away from him.

The second is Yuan Shao. After Cao Cao moved the capital to Xuchang, he basically fell out with Yuan Shao, and Yuan Shao was the strongest prince at that time, although Yuan Shao was ostensibly under the imperial court, but he also wanted to control the imperial court in his own hands, and the threat to Cao Cao was the greatest, and Yuan Shao was also the strongest and biggest enemy that Cao Cao could foresee in the short term, and it could be said that he was not a heavyweight with other princes.

The third is Lu Bu. In history, Xun Yu even proposed to Cao Cao to put Zhang Xiu on hold first and concentrate on eliminating Lu Bu when Lü Bu might return to the imperial court, believing that whether it was Zhang Xiu, who was close at hand, or Yuan Shu, who was already preparing to be the emperor, Lü Bu was the first to be eliminated before the decisive battle with Yuan Shao.

Because Lu Bu was a higher threat to Cao Cao in the decisive battle between Cao Cao and Yuan Shao than Yuan Shu, Zhang Xiu, Liu Biao and others combined.

In fact, at first, Cao Cao did not follow Xun Yu's advice to crusade against Lü Bu, and it was not until Lü Bu switched to Yuan Shu to expel Liu Bei that Cao Cao recognized Lü Bu's threat, temporarily gave up his original target Zhang Xiu, and officially sent troops to Xuzhou.

As for Yuan Shu, although he was called the emperor, Cao Cao could not tolerate him at all in law, but he and Cao Cao were enemies, and the relationship was never good, and Yuan Shu had greatly reduced the threat to Cao Cao after two defeats in a row, and the emperor was almost in name only, so Cao Cao did not put too much effort into Yuan Shu when there were many other threats.

Historically, Cao Cao's measures to proclaim Yuan Shu as emperor were more formal, and he was basically not prepared to spend a lot of energy.

Although Cao Cao did not personally command the troops to crusade against Yuan Shu, the imperial court still issued an order at the beginning of Yuan Shu's proclamation as emperor, asking Sun Ce, Chen Yu, Lü Bu and others to crusade against Yuan Shu together, but the result was that Chen Yu and Sun Ce fought first, and Lü Bu finally united with Yuan Shu again.

Later, Yuan Shu was ready to take refuge in his brother Yuan Shao and give up the throne to Yuan Shao, Yuan Shu's nephew Yuan Tan prepared to meet Yuan Shu from Qingzhou, Yuan Shu was about to pass by Xiapi at that time, so Cao Cao sent Liu Bei and Zhu Ling to Xuzhou to intercept Yuan Shu, and finally stopped Yuan Shu from going north.

When it came to the fourth year of Jian'an (199), when Yuan Shu had become the end of the strong crossbow, the imperial court ordered the then Sikong Cao Gong, the Wei general Dong Cheng, the Yizhou Mu Liu Zhang and the rebellious general Sun Ce to join forces to crusade against Yuan Shu and Liu Biao, but at that time Cao Cao was facing the threat of Yuan Shao, Dong Cheng also planned to get rid of Cao Cao, although Liu Zhang did not get along with Liu Biao, but Yizhou was also in turmoil, only Sun Ce had been ready to go, but Yuan Shu soon died of illness.

Cao Cao in the history of the Three Kingdoms can be said to be Yuan Shu's greatest enemy, but this is only for Yuan Shu. The Yuan Shu Group basically did not fight with Cao Cao during the military period, Sun Jian and Sun Ce were the two famous generals of the Yuan Shu Group in the early and late stages, but unfortunately they had no chance to fight with Cao Cao for various reasons, so Cao Cao was relatively easy when dealing with Yuan Shu.

Although Yuan Shu was also one of Cao Cao's great enemies in history, his threat to Cao Cao could be said to be relatively limited.

As for the righteousness of the imperial court, this point is as long as the face is up, although Cao Cao was the spokesperson of the imperial court at that time, but he was also a prince, and his own interests should be put first, and Cao Cao welcomed the Son of Heaven to use the Son of Heaven, and he was not really ready to work for Emperor Han Xian and be a foolish and loyal person.