thousands of civilians on his first campaign, but in 194 while on his second campaign against Tao Qian his former friend Zhang Miao raised the flag of rebellion in Yan Province. With the aid of Lü Bu, the rebels dealt several defeats to Cao Cao, taking most of the province. Eventually the tide turned on them and Cao Cao regained his territories. Zhang Miao's family was destroyed while Lü Bu fled to Xu Province. In 196 Cao Cao took control of the imperial court and moved it to Xu city. In 197 Cao Cao came into conflict with Zhang Xiu and Liu Biao. However he retreated due to news of a potential raid by Yuan Shao. In 198 Liu Bei took refuge with Cao Cao and requested his aid against Lü Bu. Cao Cao laid siege to Lü Bu in Xiapi Commandery and killed him that winter, taking control of Xu Province. Liu Bei rebelled and was driven away. Yuan Shao crossed the Yellow River with a large army in the spring of 200 but was too slow to mobilize. In the winter Cao Cao led a raiding party behind enemy lines and destroyed their supply train at the Battle of Guandu, causing Yuan Shao's army to disintegrate. Meanwhile, Liu Bei had been making trouble in Ru'nan Commandery with the bandit Gong Du. With Yuan Shao no longer posing a threat, Cao Cao returned to deal with Liu Bei, driving him away to take refuge with Liu Biao. In the summer of 202, Yuan Shao died, leaving his territory to his sons. They fought among themselves and fell prey to Cao Cao's advances. By 205 he had ousted Yuan Tan and Yuan Shang from their southern territories. Over the next two years he brought Ji Province and southern Bing Province under his control. In the summer of 207 Cao Cao made a roundabout trip north and defeated the Wuhuan at the Battle of White Wolf Mountain. They fled to Gongsun Kang in Liaodong Commandery, but he beheaded them and delivered their heads to Cao Cao. As Cao Cao prepared to campaign south in 208, Liu Biao died. His son Liu Zong surrendered while Liu Bei fled further south. Cao Cao followed and defeated Liu Bei at the Battle of Changban. Seizing the naval base at Jiangling, Cao Cao moved his new river fleet downstream. His confrontation with Liu Bei and