Editing Cao Pi (section)

===Military failures against Sun Quan===
{{main|Cao Pi's invasions of Eastern Wu}}
[[File:CaoPiPortrait.jpg|thumb|upright|right|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 [[Lü Meng's invasion of Jing Province|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 (Three Kingdoms)|Liu Ye]] suggested rejecting this offer and instead attacking 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" ({{lang|zh|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 (Three Kingdoms)|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 (Eastern Wu)|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 (China)|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."<ref>{{cite web|last=De Crespigny|first=Rafe|title=Online Publications|url=http://www.anu.edu.au/asianstudies/decrespigny/gos_ch7.pdf|work=Asian Studies|access-date=2 January 2015|quote="Alas. It is truly the will of Heaven which divides the south from the north." And he gave the order to withdraw.|url-status=dead|archive-url=https://web.archive.org/web/20110608020555/http://www.anu.edu.au/asianstudies/decrespigny/gos_ch7.pdf|archive-date=8 June 2011}}</ref>