August 11 - While conducting a siege against the Song Dynasty city known as Fishing Town in the province of Chongqing, China, the MongolKhagan, Mongke Khan, dies in the nearby hills. Persian, Chinese, and Mongol records have different accounts of how he died, including succumbing to an arrow wound received by a Chinese archer in the siege, dysentery, and even a cholera epidemic. His death sparks a succession crisis in the Mongol Empire, while his brothers Ariq Böke and Kublai soon convene their own kuriltai to elect themselves as the next Khan of Khans, opening the path to a 4- year-long civil war from 1260 to 1264. In the end, Ariq Böke surrenders to Kublai.
While engaged in a war with the Mongols, the Song Chinese official Li Zengbo writes in his Kozhai Zagao, Xugaohou that the city of Qingzhou is manufacturing one to two thousand strong iron-casedgunpowder bomb shells a month, dispatching to Xiangyang and Yingzhou about ten to twenty thousand such bombs at a time.