The Tianshi school was officially recognized by ruler Cao Cao in 215, legitimizing Cao Cao's rise to power in return.

It began when the ruler of Wei, Cao Cao, was defeated by Liu Bei and Sun Quan at the Battle of Red Cliffs.

By traditional Chinese historiography, no Three Kingdoms era officially existed, since in a legal sense the Mandate of Heaven was passed legitimately from the Han Emperor Xian to Cao Wei, and then on to the Jìn Dynasty.

Cao Cao, directly to Yuan Shao's south, was engaged in a struggle against Yuan Shu and Liu Biao, who occupied respectively the Huai River basin and middle Yangtze regions.

By 196, when he was received by Cao Cao, most of the smaller contenders for power had either been absorbed by larger ones or destroyed.

This was an extremely important move for Cao Cao following the suggestion from his primary advisor, Xun Yu, commenting that by supporting the authentic emperor, Cao Cao would have the formal legal authority to control the other warlords and force them to comply in order to restore the Han Dynasty.

Cao Cao, whose zone of control was the precursor to the state of Cao Wei, had raised an army in the winter of 189.

In 197, Yuan Shu, who was at odds with Cao Cao, Yuan Shao, and Liu Bei, felt assured of victory with his subordinate's conquests, and thus declared himself emperor of the Cheng Dynasty.

Lü Bu's men deserted him, Yuan Shu's forces never arrived as reinforcements, and he was bound by his own subordinates Song Xian and Wei Xu and executed on Cao Cao's order.

Xian was persuaded by Cao Cao ( 155 – 220 CE ), then Governor of Yan Province in modern western Shandong and eastern Henan, to move the capital to Xuchang in 196 CE.

Yuan's power was greatly diminished after Cao defeated him at the Battle of Guandu in 200 CE.

After Cao's defeat at the naval Battle of Red Cliffs in 208 CE, China was divided into three spheres of influence, with Cao Cao dominating the north, Sun Quan ( 182 – 252 CE ) dominating the south, and Liu Bei ( 161 – 223 CE ) dominating the west.

Cao Cao was very pleased and compared Zhang He's surrender to those of Wei Zi ( 微子 ) and Han Xin. ¹

In this statement, Sun Quan commented that he was very pleased with two things that Lu Su had done for him: drafting a plan for him to emerge as one of three major contending powers in China ; and helping him arrive at his resolution to ally with Liu Bei against Cao Cao just before the Battle of Red Cliffs.

After the entrenchment was completed, Yu finally sought audience with Cao and explained the situation to the latter, who was pleased and lauded the commander for his leadership quality.

Cao Cao was pleased to see his distant nephew, whom he described as the thousand-li horse of his clan.

A few weeks later, Cao Pi invited his brother to a game of weiqi during their mother's birthday.

A few weeks later, Cao Pi invited his brother to a game of weiqi during their mother's birthday.

Cao invited Xu's mother to meet him and requested for her to write a letter to her son, asking her son to come and serve him.

In ancient China, large canals for river transport were established as far back as the Warring States ( 481 – 221 BC ), the longest one of that period being the Hong Gou ( Canal of the Wild Geese ), which according to the ancient historian Sima Qian connected the old states of Song, Zhang, Chen, Cai, Cao, and Wei.

Wang Lequan, Wang Zhaoguo, Hui Liangyu, Liu Qi, Liu Yunshan, Li Changchun, Wu Yi, Wu Bangguo, Wu Guanzheng, Zhang Lichang, Zhang Dejiang, Luo Gan, Zhou Yongkang, Hu Jintao, Yu Zhengsheng, He Guoqiang, Jia Qinglin, Guo Boxiong, Cao Gangchuan, Zeng Qinghong, Zeng Peiyan, Wen Jiabao.

* Zhang Miao ( defeated by Cao Cao )

* Cao Zhang, Chinese general, son of Cao Cao ( d. 223 )

* Zhang He, general under Cao Cao ( d. 231 )

In 194, Cao Cao went to war with Tao Qian of Xu Province, because Tao's subordinate Zhang Kai had murdered Cao Cao's father Cao Song.

Liu Bei, together with his followers Zhang Fei and Guan Yu, fled to Cao Cao, who accepted him.

* Zhang He, military leader under Cao Cao ( b. 167 )

* Zhang Xiu, minor warlord who later served Cao Cao

* Cao Zhang, son of Cao Cao and general of Wei ( b. 189 )

Zhang Hong, whom Sun Ce had earlier sent as a liaison to the warlord Cao Cao, also returned from Cao's domain to assist Sun Quan.

* Yang Xiu, advisor to Cao Cao ( d. 219 )

* Cao Xiu, general of Cao Wei

This tricked the Wei general Cao Xiu, who led a large army south to support Zhou Fang.

Cao Cao proceeds to defeat his rivals such as Lü Bu, Yuan Shu and Zhang Xiu before scoring a tactical victory over Yuan Shao in the Battle of Guandu despite being vastly outnumbered.

Ma Chao and Zhang Fei attempted to trick Cao Hong into believing that they were planning to attack his rear route, but Cao Xiu saw through their ruse and advised Cao Hong to launch a counterattack.

** Ma Xiu, younger brother, executed on Cao Cao's orders after Ma Chao started a rebellion

He did this by executing Yang Xiu, a chief advisor to Cao Zhi.

He gained merits in battle when Cao Ren attacked Ruxu, and he also served in Lu Xun's Battle of Shiting against Cao Xiu.

Zhang and Ma attempted to trick Cao Hong into believing that they were planning to attack his retreat route by overtly threatening Cao Hong's rear, but Cao Xiu saw through the ruse, and Zhang Fei's forces suffered a defeat that absolved him from continuing the campaign — Lei Tong and Ren Kui were killed in action, while Wu Lan fled to take shelter from the Di tribes, where he was subsequently killed by a Di leader, Qiangduan.

In the Battle of Shiting, Zhou Fang, a provincial official feigned defection to Wei, luring a large Wei army commanded by Cao Xiu deep into Wu territory.

Lu Xun laid an ambush and destroyed most of the enemy army, while the rest were rescued by Jia Kui, who predicted the ambush and tried to convince Cao Xiu beforehand, but was rejected.

Over the next few years, Cao Mao gradually established a circle of people around him, including Sima Zhao's cousin Sima Wang, Wang Shen ( 王沈 ), Pei Xiu, and Zhong Hui, all of whom were known for their literary talent.

After the death of the southern commander of Kingdom of Wei, Xiahou Dun, 20 armies of his 26 armies were now under commandership of Cao Xiu, the newly appointed area commander under Wei emperor, Cao Pi ( son of Cao Cao ).