Battle of Changping
In 230 BC, Qin attacked Han, the weakest of the Seven Warring States, and succeeded in conquering Han within a year. Since 236 BC, Qin had been launching several assaults on Zhao, which had been devastated by its calamitous defeat at the Battle of Changping three decades ago. Although Qin faced strong resistance from the Zhao forces, led by general Li Mu, it still managed to defeat the Zhao army by using a ploy to sow discord between King Qian of Zhao and Li Mu, causing King Qian to order Li Mu's execution and replace Li with the less competent Zhao Cong. Zhao eventually fell to Qin in 228 BC after the capital city of Handan was taken. However, a Zhao noble managed to escape with remnant forces and proclaim himself king in Dai. Dai fell to Qin six years later.