Page "Sun Quan" Paragraph 16

In 219, Guan Yu advanced north, attacking Fancheng, scoring a major victory over Cao Ren.

While Fancheng did not fall at this time, Guan Yu put it under siege, and the situation was severe enough that Cao Cao considered moving the capital away from Xu.

However, Sun Quan, resentful of Guan Yu's prior constant instigation of hostilities ( including seizing Sun's food supplies to use for his campaign north ), took the opportunity to attack Guan from the rear, and Guan's forces collapsed.

Guan Yu was captured by Sun Quan's general Lü Meng ; once captured, Sun Quan executed Guan Yu, Jing Province came under Sun's control, and the Sun-Liu alliance ended.

Sun Quan nominally submitted to Cao Cao and urged him to take the throne but Cao refused.