Regalianus vs Yuan Shao

Regalianus, governor of Pannonia, was proclaimed emperor by the local legions during the Crisis of the Third Century. His usurpation was a response to barbarian invasions and the perceived weakness of Gallienus's central authority.

Regalianus's brief reign ended when he was defeated and killed in battle against the Roxolani, a Sarmatian tribe that had invaded Pannonia. His death occurred shortly after his proclamation, and his rebellion collapsed.

Yuan Shao's forces clashed with Gongsun Zan's elite cavalry at Jieqiao. Despite being outnumbered, Yuan Shao's infantry, using crossbows and shields, repelled the charge and secured a tactical victory, solidifying his control over northern Hebei.

After years of war, Yuan Shao defeated his rival Gongsun Zan at the Battle of Yijing, conquering the four provinces of Ji, Qing, You, and Bing. This made him the most powerful warlord in northern China, commanding a vast territory and army.

Yuan Shao led a massive army south against his rival Cao Cao. At Guandu, Cao Cao's smaller force launched a surprise attack on Yuan Shao's supply depot at Wuchao, burning it. Yuan Shao's army collapsed, and he was decisively defeated, losing his strategic advantage.

Yuan Shao died in Ye city, reportedly from illness and frustration following his defeat at Guandu. His death triggered a succession struggle between his sons Yuan Tan and Yuan Shang, which further weakened his faction and allowed Cao Cao to conquer the north.