The Tumu Crisis (simplified Chinese: 土木之变; traditional Chinese: 土木之變; pinyin: Tŭmù zhī Bìan); also called the Crisis of Tumubao (simplified Chinese: 土木堡之变; traditional Chinese: 土木堡之變; pinyin: Tǔmù zhī Biàn) or Battle of Tumu Fortress (Chinese: 土木之役; pinyin: Tǔmù zhī Yì), was a frontier conflict between the Oirat Mongols and the Chinese Ming Dynasty which led to the capture of the Zhengtong Emperor on September 1, 1449 and the loss of an army o...