On this day, 791 years ago, on February 9, 1234 (January 10, 1234, the lunar calendar), Mongolia destroyed the Jin Dynasty. After the establishment of the Mongolian regime of Genghis Khan, he launched a war against Jin in order to get rid of his enslaved status. In 1211, Genghis Khan personally led his troops to attack Jin. In three years, more than 90 counties were conquered. The Jin rulers were forced to move the capital from Zhongdu (present-day Beijing) to Kaifeng and seek peace with Mongolia. In the autumn of 1214, Genghis Khan once again led troops south, broke through Zhongdu, plundered Bianjing and returned. After that, the main force of the Mongolian army turned to the Western Expedition, and the Jin Dynasty was given more than 20 years of delay. Wogetai inherited the throne and continued the war against Jin. The Mongolian aristocrats plundered and slaughtered wantonly in the war, destroying everything they passed. Thousands of miles east of the Lianghe River,"the people killed almost all of them. Gold, silk, children, cattle, sheep, horses and livestock were swept away. Houses and houses were burned down, and cities and hills were destroyed."("Miscellaneous Notes on the Government and the Government since Jianyan"). The people of the Central Plains tenaciously resisted the Mongolian army. The Mongolian aristocrats were unable to achieve their goal of destroying the Jin Dynasty for a long time. Wogotai Khan instead adopted the strategy of "joining the Song Dynasty to attack the Jin Dynasty" and formed an alliance with the Southern Song Dynasty, agreeing that the area south of the Yellow River would be returned to the Southern Song Dynasty after the destruction of the Jin Dynasty. The Mongolian army used the Southern Song Dynasty to bypass Tongguan, the military town of the Jin Dynasty, and captured Kaifeng in 1233, forcing Aizong of the Jin Dynasty to flee to Caizhou (present-day Runan, Henan). In 1234, the Southern Song Army and the Mongolian Army jointly captured Caizhou, and the Jin Dynasty fell.