At the end of 221, Shu invaded Wu in response for Guan Yu's killing and the loss of Jing Province by Wu. In the spring of 222, Liu Bei arrived at the scene to personally take command of the invasion. Sun Quan dispatched Lu Xun to command over the defence of Wu against the invasion by Shu. Against the advice of his subordinates, Lu Xun waited until Liu Bei was committed along the Yangtze below the Yangtze Gorges. Finally, in the sixth month of 222, Lu Xun launched a series of fire attacks against the flank of Liu Bei's extended position which caused disorder in the Shu army and Liu Bei's retreat to Baidi (near present-day Fengjie). Afterwards in 222, Sun Quan renounced his suzerainty to Wei and declared the independence of Wu. In 223, Liu Bei perished at Baidi. Zhuge Liang now acted as a regent for Liu Shan (aged 17) and held control of the Shu government. Shu and Wu resumed their diplomatic relations by re-establishing peace and alliance in the winter of 223. On 23 June 229, Sun Quan proclaimed himself as the Emperor of Wu.