Chongzhen executed his best general on enemy rumours — the Ming fell 14 years later

Yuan Chonghuan was the Ming dynasty's most capable military commander against the rising Later Jin (Manchu) state. In 1626, defending the fortress of Ningyuan with only 9,000 men against Nurhaci's 130,000-strong army, he used European cannon to shatter the siege. Nurhaci was mortally wounded. A second victory at Ning-Jin in 1627 forced his successor Huang Taiji to withdraw. The victories were the first major checks on Manchu expansion in a generation.

But Yuan was a victim of his own success. The eunuch faction under Wei Zhongxian forced his retirement in 1627. When the Chongzhen Emperor ascended the throne in 1628, he purged the eunuchs and reinstated Yuan, granting him the Sword of Honour and full authority over the northeast frontier. Yuan promised to recover the lost territories within five years. For a brief moment, the Ming had a unified command and a coherent strategy.

Two events destroyed him. First, he executed the independent general Mao Wenlong for insubordination — a legally questionable act that made powerful enemies at court. Second, in 1629 Huang Taiji bypassed Yuan's fortified line, broke through an unguarded pass, and marched directly on Beijing. Yuan raced back with his cavalry and drove the Manchus from the capital. But Huang Taiji had planted a story: captured eunuchs were allowed to 'overhear' that Yuan was negotiating a truce. The rumour reached the emperor.

On 13 January 1630, Yuan was arrested at a court audience on charges of collusion with the enemy. No credible evidence was produced. On 22 September 1630, he was put to death in Beijing. The Qing emperor Qianlong would later exonerate him after finding the captured Ming records. Without Yuan, the Ming defence of the north collapsed. The dynasty fell in 1644.