Esen Taishi

Esen Taishi (Mongolian: Эсэн тайш; died 1455) was a powerful Oirat Khagan of Northern Yuan dynasty based in Mongolia in the 15th century. He is best known for capturing the Zhengtong Emperor of the Ming dynasty in 1450 after the Battle of Tumu Fortress and briefly reuniting the Mongols. The Oirats reached their peak under his rule.

Youth and early career

Esen was born to his father, Toghon, the Choros taishi (grand preceptor, from 太師) who had expanded Oirat territory substantially, with more Mongol tribes acknowledging his supremacy. As an Oirat, Esen was not descended from Genghis Khan, and this hampered his claim to the title of great khan.

His early campaigns were against the Chaghatayid khans of Moghulistan. Esen three times defeated and twice captured the Moghuli ruler Uvais (Ways Khan) (1418–1432). Esen released him out of respect for his Chinggisid blood in both cases. The second time, Uvais granted Esen his sister Makhtum Khanim, who bore his two sons. Esen had to nominally convert to Islam in order to marry the Muslim princess, but remained effectively a shamanist.