Editing Sun Quan (section)

==Uneasy alliance with Liu Bei==
{{Further|Battle of Jiangling (208)|Sun–Liu territorial dispute}}

[[File:Sun Quan statue.jpg|right|thumb|250px|Statue of Sun Quan.]]

Immediately after Cao Cao withdrew, Sun Quan took over the northern half of [[Jing Province]]. Liu Bei marched south and took over the southern half. The Sun-Liu alliance was further cemented by a marriage of Sun Quan's younger sister, [[Lady Sun]], to Liu Bei. Zhou Yu was suspicious of Liu Bei's intentions, however, and suggested to Sun Quan that Liu be seized and put under house arrest (albeit be very well-treated) and his forces be merged into Sun's; Sun Quan, believing that Liu Bei's forces would rebel if he did that, declined. Sun Quan did agree to Zhou Yu's plans to consider attacking [[Liu Zhang (warlord)|Liu Zhang]] and [[Zhang Lu (Han dynasty)|Zhang Lu]] (who controlled the modern southern [[Shaanxi]]) to try to take over their territories, but after Zhou Yu died in 210, the plans were abandoned. However, Sun Quan was able to persuade the warlords in [[Jiao Province]] to submit to him, and they became part of his domain. He then yielded parts of northern Jing Province to Liu Bei as well, agreeing with Liu that the south was insufficient to supply his troops. At the same time, Sun Quan appointed his subordinate Bu Zhi as the Inspector ({{lang|zh|刺史}}) of Jiao Province to replace Lai Gong. Shi Xie led his followers to submit to Bu Zhi's governorship. Sun Quan took over the entire Jiao Province.

In 211, Sun Quan moves his headquarters from Dantu to the city of Moling, and in the next year he rebuilt the walls and renamed the city [[Jiankang|Jianye]]. This new location gave him better control of the Yangtze River and better communications with his various other commanders. He also constructed fortresses at Ruxu, since [[Lü Meng]] anticipated an invasion there from Cao Cao.

The invasion Lü Meng expected came at the start of 213. Sun Quan personally led the army there to resist Cao Cao and relied heavily on the fortresses Lü Meng built to give his soldiers strong positions from which to defend. At one point, Cao Cao tried to send his navy across the river to break Sun Quan's lines, but Sun Quan's own ships surrounded them and destroyed them. Due to the stalemate in the war, Sun Quan drove a big ship to enter the military camp of Cao Cao on the other side of Yangtze River to observe his enemy situation. Cao Cao was very impressed with the military discipline of his opponent so he said that he should have a child like Sun Quan and didn't launch an attack on this occasion. Sun Quan ordered people to play music on the ship and returned to his camp safely. Ultimately, Lü Meng's defences held and Sun Quan wrote a letter to Cao Cao to warn that the spring rains would come a month later, Cao Cao had to take his advice and pull back.

After Cao Cao's defeat at Ruxu, many people along the Yangtze River fled south to join Sun Quan. With the exception of Wan County and the immediate area, the region became abandoned. In 214, Cao Cao sent a man named Zhu Guang to Wan County with orders to revitalise the region and bring it under Cao Cao's control. Zhu Guang began extensive agricultural projects, and he also stirred up bandits and malcontents into rebellion in Sun Quan's territory. Lü Meng feared that if Zhu Guang's programmes were successful, it would make Cao Cao's hold in the area unbreakable and urged for a campaign against Huan. Sun Quan followed Lü Meng's strategy and used the seasonal flooding to travel to the city by boat, which allowed them to attack unexpectedly. Rather than a lengthy siege, Lü Meng, [[Gan Ning]] and [[Ling Tong]] led a quick strike and broke Zhu Guang's defences, capturing the city.

After Liu Bei's conquest of [[Yi Province]], he was able to supply his troops on his own, so Sun Quan sent [[Lu Su]] as an emissary to demand for the return of Jing Province, but Liu Bei refused. Sun Quan then sent [[Lü Meng]] and [[Ling Tong]] to lead 20,000 men to attack southern Jing Province and they succeeded in capturing [[Changsha]], [[Guiyang]], and [[Yongzhou|Lingling]] commanderies. Meantime, [[Lu Su]] and [[Gan Ning]] advanced to Yiyang ({{lang|zh|益陽}}) with 10,000 men (to block [[Guan Yu]]) and took over command of the army at Lukou ({{lang|zh|陸口}}). Liu Bei personally went to [[Gong'an County]] and Guan Yu led 30,000 men to Yiyang. When an all-out war was about to break out, the news that Cao Cao planned to attack [[Battle of Yangping|Hanzhong]] was received by Liu Bei, and he requested for a border treaty with Sun Quan as he became worried about Cao Cao seizing Hanzhong. Liu Bei asked Sun Quan to give him back Lingling Commandery and create a diversion for Cao Cao by [[Battle of Xiaoyao Ford|attacking Hefei]]; in return, Liu Bei ceded [[Changsha]] and [[Guiyang]] commanderies to Sun Quan, setting the new border along the [[Xiang River]]. Sun Quan's attack on Hefei was disastrous - he was nearly captured on one occasion, if not saved by Ling Tong.

In 217, Cao Cao brought a massive army to attack Ruxu again. Sun Quan personally led 70,000 men to defend the city, though he left actual command of the battle to Lü Meng. It was a furious campaign, and after several weeks of gruelling battle, Lü Meng's defences held and the spring floods forced Cao Cao to retreat once again.

Still, this was not a complete victory. Most of Cao Cao's army was still intact and he had a huge force under Xiahou Dun north of Sun Quan's position. This resulted in a stalemate in which as long as Sun Quan kept his army in Ruxu, Xiahou Dun could not hope to invade him; but as soon as Sun Quan pulled out of Ruxu, Xiahou Dun could break through. Also, Xiahou Dun's force was simply too large and too well-entrenched to be driven away. Sun Quan had no military options, so he settled on a diplomatic solution. In 217, Sun Quan allied with Cao Cao, recognising him as the legitimate representative of the Han central government. While officially this was a surrender, Cao Cao knew that Sun Quan would not be content with being treated like a subject, so he confirmed all of the titles Sun Quan had claimed for himself and formalised his control over the lands he held. Sun Quan was permitted to continue to rule independently but was now officially one of Cao Cao's subordinates.