Quan did agree with Zhou Yu's suggestion to consider attacking the warlords Liu Zhang and Zhang Lu, who controlled parts of western China, including present-day southern Shaanxi and the Sichuan Basin. The plan was not set into motion and eventually aborted when Zhou Yu died in 210. Even though Sun Quan did not expand his borders west, he managed to persuade several local leaders in present-day Guangdong, Guangxi and northern Vietnam to submit to him, and these territories became part of his domain. Sun Quan then agreed to "lend" northern Jing Province to Liu Bei as well when the latter complained that the south lacked resources to sustain its military. Cao Cao's northwestern campaign (211) Cao Cao, after resting his forces for several years in light of his defeat at the Battle of Red Cliffs, made a major advance again in 211, this time to ostensibly attack Zhang Lu of Hanzhong. Warlords Han Sui and Ma Chao, who controlled Liang and Yong provinces, suspected that Cao Cao had designs on them and launched attacks in retaliation. A coalition of forces from west of Hangu Pass, led by Ma Chao and Han Sui, was defeated by Cao Cao at the Battle of Tong Pass in 211, and their territories were annexed by Cao over the next few years. Liu Bei's takeover of Yi Province (212–214) Liu Zhang of Yi Province became worried of possible attacks from Zhang Lu and Cao Cao, so he sent Fa Zheng to invite Liu Bei into his domain to help him defend against Zhang Lu and Cao Cao. Fa Zheng was unimpressed with Liu Zhang's governorship and wanted Liu Bei to replace his lord, so he urged Liu Bei to use the opportunity to take control of Yi Province. Liu Bei heeded Fa Zheng's suggestion and led his army into Yi Province, where he received a warm welcome from Liu Zhang. Liu Zhang sent Liu Bei to the station at Jiameng Pass in northern Yi Province to resist Zhang Lu. In 212, Liu Bei and Liu Zhang turned hostile towards each other and waged war. Zhuge Liang led a detachment of Liu Bei's forces left in Jing Province to join his lord in attacking Liu Zhang. Guan Yu remained behind to defend Jing Province. In 215, Liu Bei had defeated much of Liu Zhang's forces and besieged him in his capital of Chengdu. Liu Zhang surrendered