Zhengtong Emperor
The Inner City walls withstood a major test following the Tumu Crisis of 1449 when the Zhengtong Emperor was captured by Oirat Mongols during a military campaign near Huailai. The Oirat chieftain, Esen Tayisi, then drove through the Great Wall and marched on the Ming capital with the captive emperor in hand. Defense Minister Yu Qian rejected Esen's demands for ransom despite the Zhengtong Emperor's pleadings. Yu said the responsibility to protect the country took precedence over the Emperor's life. He rejected calls by other officials to move the capital to the South and instead elevated the Zhengtong Emperor's younger half-brother to the throne and assembled 220,000 troops to defend the city. Ming forces with firearms and cannons ambushed the Mongol cavalry outside Deshengmen, killing Esen's brother in the barrage, and repelled another attack on Xizhimen. Esen retreated to Mongolia and three years later, returned the captive Zhengtong Emperor with no ransom paid. In 1457, the Zhengtong Emperor reclaimed the throne and had Yu Qian executed for treason. Yu Qian's home near Dongdan was later made into a temple in his honor.