In the year 219 AD, Cao Cao had a bad time.
Cao Cao's important general Xiahou Yuan was defeated by Huang Zhong, and Guan Yu, who was sitting in Jingzhou in the Central Plains, led his army north to attack Fancheng and Xiangyang, and even drowned seven armies.
However, what was unexpected was that when Guan Yu was in the limelight, Guan Erye retreated to Maicheng in defeat soon after, and finally died with hatred. 
So, as the top military general of the Three Kingdoms, how many fierce generals did Guan Yu encounter on the road to defeat?
1. The potential crisis in Jingzhou.
Although it seems to many that the three kingdoms of Wei, Shu and Wu are usually Shu and Wu joining forces to fight against Wei, in the matter of Guan Yu, Wei and Wu joined hands to defeat Guan Erye.
Why is that?
Could it be that Sun Quan didn't understand that only by uniting the weak could the safety of Soochow be ensured? 
Sun Quan understood, of course, but he knew better that if Jingzhou could not be recaptured, Eastern Wu would inevitably face the threat of Cao Cao. Although Cao Cao's fate is difficult, the prospects of Soochow will definitely be overshadowed!
Looking at the map, we can see that Jingzhou, that is, today's Hubei and Hunan, plus the land of Bashu, in 219 AD, Liu Bei had completely mastered the middle and upper reaches of the Yangtze River.
The core of Soochow's rule was located in the area of present-day Nanjing, Jiangsu, along the lower reaches of the Yangtze River.
If Cao Cao's army attacked from the north, Eastern Wu could rely on the Yangtze River to defend it. 
But if Liu Bei rejuvenated the water division and attacked south along the Yangtze River, Eastern Wu would face a more urgent crisis than the Battle of Chibi.
It is worth noting that the process of the Western Jin Dynasty's destruction of Eastern Wu was completed from Bashu and south along the Yangtze River.
Therefore, around the Jingzhou issue, Sun Quan, Lu Su and others launched many fierce competitions with Liu Bei, Zhuge Liang, and Guan Yu.
Long before the two sides broke up completely, Lu Su led a large army to confront Liu Bei, which was one of their long confrontations.
However, Liu Bei was hesitant to hand over Jingzhou to Sun Quan. He felt uneasy inside, as if a knife was hanging from his head. 
In this case, if there is an opportunity to frame Liu Bei and recapture Jingzhou, do you think Sun Quan will hesitate?
Therefore, Guan Yu made it clear in Jingzhou that although he and Sun Quan were friendly on the surface, and might even become in-laws, once Sun Quan made a move, Guan Yu would never be soft.
Because for a true politician, marriage is just a means.
For a qualified emperor, if necessary, he can even get rid of his own son, let alone the so-called in-laws?
Secondly, Guan Yu had too many enemies to face, so his defeat was not surprising.
In 219 AD, Guan Yu led most of the Jingzhou troops north to march into the Central Plains. 
On the defensive line of Fancheng and Xiangyang, he first had to face two powerful generals, Cao Ren and Man Chong.
In the past two years, Cao Ren and Man Chong have been difficult opponents to deal with, although Cao Ren is often defeated and has limited attack power, but in terms of defense, he is also considered a top existence in the Three Kingdoms.
After the Battle of Chibi, Cao Ren led the remnants of the defeated army and adopted a defensive counterattack strategy, almost forcing Zhou Yu to death.
As for the full favor, it is a leader in both civil and military affairs.
In addition, the pressure on the defense lines of Xiangyang and Fancheng was already huge, so this battle was quite difficult. 
In addition, Cao Wei also dispatched the generals Ban and Pang De to help, although these two failed to play much role and were eventually flooded by Guan Yu, but Cao Wei's importance to this battle is undeniable.
After learning of the news that Yu was captured in the Forbidden War, Cao Cao quickly dispatched Xu Huang, a general who was also a good general of the Five Sons, to support. At the same time, Cao Cao sent people to get in touch with Sun Quan, and the two sides hit it off and jointly dealt with Guan Yu, launching an unprecedented encirclement and suppression.
The two great governors of Eastern Wu, Lü Meng and Lu Xun, joined forces, crossed the river in white, and took advantage of the opportunity of Jingzhou to launch a fierce attack on Guan Yu's rear. 
After learning the news of the attack on the rear, Guan Yu had no choice but to withdraw his troops, but was again attacked by the joint onslaught of Xu Huang and Cao Ren, and finally routed south.
It is worth noting that while attacking Jingzhou, Eastern Wu also sent three generals, Jiang Qin, Han Dang and Zhou Tai, to attack Guan Yu's retreat route, which put Guan Yu in a very difficult situation, and finally had to defeat Maicheng.
However, it doesn't end there.
In the process of Guan Yu's breakthrough, the generals of Eastern Wu Ding Feng and Xu Sheng blocked his way, plus Zhou Tai, Han Dang and others who were chasing all the way, Guan Yu almost alone against all the famous generals of Eastern Wu, plus Cao Wei's Xu Huang, Cao Ren, Man Chong, Yu Ban, etc.
In fact, in the history of the Three Kingdoms, only the second master was able to withstand the siege of so many famous generals. 
However, if it was just a dispute between these two parties, Guan Yu might not have such a miserable ending. The final blow turned out to come from within Shu Han, what was going on?
In fact, the main reason why Guan Yu fell into such a painful defeat was that Jingzhou fell too quickly, and the reason why Jingzhou fell was because of the emergence of traitors.