The commandery was north of Qing province, where Yuan Tan had held the title of Inspector (刺史) since his father's time.
Here he was joined by his former subordinates such as Wang Xiu and Guan Tong (管統), but at the same time some of them rebelled against him under Liu Xun (劉詢) - Yuan Tan's foothold in Nanpi could hardly have been stable.
Yuan Tan's key advisor Guo Tu summarized the situation and proposed an unlikely alliance: "Now, general, your domains are small and your soldiers are few, your supplies are lacking and your forces are weak.
If [Yuan Shang]'s army is defeated, his men will come fleeing, and they can be appropriated to resist Duke Cao.
"[2]Guo Tu's proposal was a marked departure from the calls for reconciliation by Wang Xiu and Liu Biao, and though Yuan Tan was initially reluctant to act on this advice, he soon sent Xin Pi to negotiate with his father's nemesis.
Xun Yu reasoned that Liu Biao was not ambitious enough to be a threat, so the time was right to take advantage of the Yuan family feud before the brothers reunited.
Yuan Shang hurriedly led his army from Pingyuan back to Ye in response to the new alliance, while some of Yuan Shang's officers like the brothers Lü Kuang (呂曠) and Lü Xiang (呂翔) defected to Cao Cao's side.
The Lü brothers were rewarded with enfeoffment, but Yuan Tan offered them seals in an attempt to persuade them to join him instead.
Despite his recent achievements, he had only reestablished himself in the northern part of Ji province for a few weeks at most and could not have held Longcou and Nanpi securely.
Cao Cao's envoy to the Wuhuan Qian Zhao (牽招) made an impressive show of force against a rival envoy at Supuyan's court and successfully convinced the Wuhuan king to disband the relief force.
Yuan Tan himself fell off his horse while fleeing Cao Chun's men, and in a desperate bid to save himself, he turned to his pursuer and pled: "Tut!
As Cao Cao entered the city, he heeded the advice of Li Fu (李孚), the newly surrendered Registrar of Ji Province (冀州主簿), to not sack the city, and sent Li Fu to announce to the populace that business should carry on as usual.
He also suppressed private feuding and vendetta, while also setting some sumptuary laws forbidding excessive funerary rites, over-extravagant tomb constructions, and the erection of steles.
Wang Song (王松) in Zhuo Commandery and Xianyu Fu (鮮于輔) in Yuyang Commandery pledged allegiance to Cao Cao, while in Yuan Xi's headquarters he was faced with internal mutiny by Jiao Chu (焦觸) and Zhang Nan (張南).