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 Lingling commanderies. Meantime, Lu Su and Gan Ning advanced to Yiyang () with 10,000 men (to block Guan Yu) and took over command of the army at Lukou (). 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 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 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.