Mongol-Jin War: The Mongols begin their siege on Kaifeng, the capital of the Jin dynasty.
In the Mongol siege of Kaifeng from 1232 to 1233, the Mongol Empire captured Kaifeng, the capital of the Jurchen Jin dynasty. The Mongols and Jurchens had been at war for nearly two decades, beginning in 1211 after the Jurchens refused the Mongol offer to submit as a vassal. gedei Khan sent two armies to besiege Kaifeng, one led by himself, and the other by his brother Tolui. Command of the forces, once they converged into a single army, was given to Subutai who led the siege. The Mongols arrived at the walls of Kaifeng on April 8, 1232.
The siege deprived the city of resources, and its residents were beset with famine and disease. Jurchen soldiers defended the city with fire lances and bombs of gunpowder, killing many Mongols and severely injuring others. The Jurchens tried to arrange a peace treaty, but the assassination of a Mongol diplomat foiled their efforts. Emperor Aizong, the Jurchen emperor, fled the city for the town of Caizhou. The city was placed under the command of General Cui Li, who executed the emperor's loyalists and promptly surrendered to the Mongols. The Mongols entered Kaifeng on May 29, 1233, and looted the city. The dynasty fell after the suicide of Aizong and the capture of Caizhou in 1234.
The Mongol conquest of the Jin dynasty, also known as the Mongol–Jin War, was fought between the Mongol Empire and the Jurchen-led Jin dynasty in Manchuria and north China. The war, which started in 1211, lasted over 23 years and ended with the complete conquest of the Jin dynasty by the Mongols in 1234.