In 1691, the leaders of the Tüsheet Khan, the Jasaghtu Khan, and the Setsen Khan fled to Inner Mongolia where they pledged fealty to the Kangxi Emperor of the Qing dynasty in return for protection against the invading Dzungar (western) Mongolian forces under Galdan Boshugtu Khan. After the Qing's victory over the Dzungars at the Battle of Jao Modo in 1697, the three khanates became provincial subdivisions or "aimags" of the Manchus and their respective khans were made nominal leaders. In 1725, the Qing created a fourth aimag, Sain Noyon Khan Aimag, carved out of 19 "khoshuu" (sub-districts) in western Tüsheet Khan Aimag. In 1930, following the Mongolian Revolution of 1921, the four aimags were divided into the present day 21 smaller aimags, which were subdivided into sums.