The battle in October 202 was the first between the two factions since the death of Yuan Shao four months earlier.
After years of civil war since the failed campaign against Dong Zhuo, two major factions emerged from the multitudes of feuding warlords: one led by the northern warlord Yuan Shao who nominally controlled the provinces of Ji, Qing, Bing, and You; the other led by his former friend and subordinate Cao Cao, who, in addition to the three provinces of Yan, Yu, and Xu, also had the imperial court and the Han Emperor Xian under his control.
Yuan Shao died in June 202, said to be in frustration and anger at his defeat, leaving his sons to succeed his legacy.
Cao Cao initially suggested that the goods should be brought by land instead, but since Li Dian argued that Gao Fan's men were lightly armed and not prepared for naval warfare, he allowed Li Dian and Cheng Yu to attack Gao Fan.
The official Wei records in Records of the Three Kingdoms indicate that Cao Cao won successive battles over the course of six months, forced the Yuan brothers out of Liyang but suddenly lifted the siege of the Yuan headquarters of Ye and withdrew to Xu City.
However, Yuan Shao's post-biography in the Records, the Book of the Later Han, and contemporary references such as the Chu Shi Biao contradict the Wei account, while the fact that the operation took so long also suggests that it might not have gone as smoothly as Cao Cao's official biography stated.
In response, Yuan Shang left Shen Pei to guard Ye while he brought his army in person to reinforce Liyang.
[5] The two sides fought west and south outside Liyang, where remains of the defenses used in the battle could still be seen during the Tang dynasty.
The setback caused Cao Cao to turn his attention away from the Yuan headquarters for the moment, as he turned east to storm the city of Yin'an (陰安; in present-day Qingfeng, Henan) and collected grains from the granaries in southern Wei Commandery (around present-day Handan, Hebei).
By the time Cao Cao was ready to attack Ye again in late May or June 203, his advisor Guo Jia offered advice to the contrary to take advantage of the Yuan brothers' simmering tensions: "Yuan Shao loved those two sons, but neither was proclaimed as his heir.
He stayed in Xu City for the next three months, possibly to assert his authority to prevent any disorder that might arise from his extended absence.
During his stay there, he issued two proclamations that sought to punish and demote unsuccessful officers, with the reason that ranks and rewards should not be given to those who failed to earn them.