Cao Pi

In the winter of 220, Cao Pi made his move for the imperial throne, strongly suggesting to Emperor Xian that he should yield the throne. Emperor Xian did so, and Cao Pi formally declined three times (a model that would be followed by future usurpers in Chinese history), and then finally accepted, establishing the state of Cao Wei. This event marked the official end of the Han dynasty and the beginning of the Three Kingdoms period. The dethroned Emperor Xian was granted the title "Duke of Shanyang" (山陽公). Cao Pi granted posthumous titles of emperors to his grandfather Cao Song and his father Cao Cao, while his mother Queen Dowager Bian became empress dowager. He also moved the imperial capital from Xuchang to Luoyang.

A block print of Cao Pi wearing anachronistic clothing.

After news of Cao Pi's ascension (and an accompanying false rumour that Cao Pi had executed Emperor Xian) arrived in Liu Bei's domain of Yi Province (covering present-day Sichuan and Chongqing), Liu Bei also declared himself emperor in May 221, establishing the state of Shu Han. Sun Quan, who controlled the vast majority of southeastern and southern China, did not take any affirmative steps one way or another, leaving his options open.

An armed conflict between Liu Bei and Sun Quan quickly materialised, because in late 219 Sun Quan had sent his general Lü Meng to invade Jing Province and seize the territories from Liu Bei, which resulted in the death of Liu's general Guan Yu. To avoid having to fight on two fronts, Sun Quan formally paid allegiance to Cao Pi, expressing his willingness to become a vassal under Wei. Cao Pi's strategist Liu Ye suggested to reject and instead attack Sun Quan on a second front. This would effectively partition Sun Quan's domain with Shu, and would eventually allow Cao Pi to destroy Shu as well. Cao Pi declined this suggestion, in a fateful choice that most historians believe doomed his empire to ruling only northern and central China; such an opportunity would not come again. Indeed, against Liu Ye's advice, Cao Pi granted Sun Quan the title "King of Wu" (吳王) and the nine bestowments.

Sun Quan's submission did not last long. After Sun Quan's forces, under the command of Lu Xun, defeated Shu forces at the Battle of Xiaoting in 222, Sun Quan began to distance himself from Wei. When Cao Pi demanded that Sun Quan send his heir apparent, Sun Deng, to Luoyang as a hostage, Sun Quan refused and formally broke ties with Wei. Cao Pi personally led an expedition against Sun Quan, and in response, Sun Quan declared independence from Wei, establishing the state of Eastern Wu (but he continued ruling as "King of Wu" and did not declare himself emperor until 229). By this time, having defeated Shu, the Wu forces enjoyed high morale and effective leadership from Sun Quan, Lu Xun and a number of other capable generals. Cao Pi's forces were not able to make significant advances against them despite several large-scale attacks in the next few years. The division of the former Han Empire into three states has become firmly established, particularly after Liu Bei's death in 223. The Shu chancellor Zhuge Liang, serving as regent for Liu Bei's son and successor Liu Shan, re-established the alliance with Wu, resulting in Wei having to defend itself on two fronts and unable to conquer either. Exasperated, Cao Pi made a famous comment in 225 that "Heaven created the Yangtze River to divide the north and the south."[9]

Cao Pi was generally viewed as a competent, but unspectacular, administrator of his empire. He commissioned a number of capable officials to be in charge of various affairs of the empire, employing his father's general guidelines of valuing abilities over heritage. However, he was not open to criticism, and officials who dared to criticise him were often demoted and, on rare occasions, put to death.

Since Cao Pi was still fearful and resentful of Cao Zhi, he soon had the latter's fief reduced in size and had a number of his associates executed. Ding Yi, who was chief among Cao Zhi's strategists, had his whole clan exterminated as a result of assisting the latter in the past. In summary, under regulations established by Cao Pi, not only were the Wei princes (unlike princes of the Han dynasty) distanced from central politics, they also had minimal authority even in their own principalities and were restricted in many ways, particularly in the use of military force.

Cao Pi was recorded to frequently ridicule his subordinates. For example, Yu Jin was captured by Liu Bei's general Guan Yu at the Battle of Fancheng in 219, and was later taken back to Wu and detained there after the Wu invasion of Jing Province. Yu Jin was allowed to return to Wei after Wu briefly became a vassal state under Wei in 221. Cao Pi reinstated Yu Jin as General Who Pacifies the Borders (安遠將軍) and announced that he would send Yu Jin back to Eastern Wu – where he had been imprisoned – as an envoy. However, before Yu Jin's departure, he was instructed to travel to Ye to pay his respects at Cao Cao's tomb. When Yu Jin arrived, he found that the emperor had commissioned artists to paint, in his father's tomb, scenes of the Battle of Fancheng. These scenes showed Yu Jin begging for his life to be spared and succumbing to the victorious Guan Yu, while his subordinate Pang De was shown dying an honourable death by resisting the invading forces to his last breath. Upon seeing the vivid mural, Yu Jin was so filled with regret and shame that he fell ill and soon died. Cao Pi further gave the deceased Yu Jin a negative-sounding posthumous title, "Marquis Li" (厲侯), for people to remember the latter as the "stony marquis (or vicious marquis)".[10] Wang Zhong, a general who followed Cao Cao for many years, was also a subject of ridicule by Cao Pi.

An immediate issue after Cao Pi became emperor in 220 was who the empress would be. Lady Zhen was his wife. Cao Pi summoned Lady Zhen to Luoyang, but Lady Zhen refused because of her poor health. In August 221, Lady Zhen died and the position of empress went to Guo Nüwang.[11]

Guo Nüwang did not bear Cao Pi any children. Cao Rui was the eldest of Cao Pi's sons, but because of his mother's death, he was not instated as the crown prince. Instead, Cao Rui was appointed "Prince of Pingyuan" after his father's ascension to the throne. Cao Pi did not appear to have seriously considered any other son as heir. (It might have been because the other sons were all significantly younger, although their ages were not recorded in history.) In the summer of 226, when Cao Pi was seriously ill, he finally named Cao Rui as his crown prince. On his deathbed, he entrusted Cao Rui to the care of Cao Zhen, Chen Qun and Sima Yi. Following his father's death, Cao Rui ascended the throne at the age of 21.