The first Mongol invasions of Burma (Myanmar) (Burmese: မွန်ဂို–မြန်မာ စစ် (၁၂၇၇–၁၂၈၇); Chinese: 元緬戰爭) were a series of military conflicts between Kublai Khan's Yuan dynasty, a division of the Mongol Empire, and the Pagan Empire took place between 1277 and 1287. The invasions toppled the 250-year-old Pagan Empire, and the Mongol army seized Pagan territories in present-day Dehong, Yunnan and northern Burma to Tagaung. The invasions ushered in 250 years of political fragmentation in Burma and the rise of ethnic Tai-Shan states throughout mainland Southeast Asia. The Mongols first demanded tribute from Pagan in 1271–72, as part of their drive to encircle the Song dynasty of China. When King Narathihapate refused, Emperor Kublai Khan himself sent another mission in 1273, again demanding tribute. It too was rejected. In 1275, the emperor ordered the Yunnan government to secure the borderlands in order to block an escape path for the Song, and permitted a limited border war if Pagan contested. Pagan did contest but its army was driven back at the frontier by the Mongol Army in 1277–78. After a brief lull, Kublai Khan in 1281 turned his attention to Southeast Asia, demanding tribute from Pagan, the Khmer Empire, Đại Việt and Champa. When the Burmese king again refused, the emperor ordered an invasion of northern Burma. Two dry season campaigns (1283–1285) later, the Mongols had occupied down to Tagaung and Hanlin, forcing the Burmese king to flee to Lower Burma. The Mongols organized northern Burma as the province of Zhengmian. Ceasefire negotiations began in 1285, and ended with Narathihapate finally agreeing to submit in June 1286. The Burmese embassy, received by the emperor in Beijing in January 1287, agreed to a treaty that acknowledged the suzerainty of the Mongol Empire over the Pagan Empire and annual payments in taxes to the Yunnan government in exchange for the evacuation of Mongol troops from northern Burma. But the treaty never really took effect as Narathihapate was assassinated in July 1287, and no authority who could honor the treaty emerged. The Mongol command at Yunnan now deemed the imperial order to withdraw void, and ordered an invasion of central Burma. They may not have reached Pagan, and even if they did, after having suffered heavy casualties, they returned to Tagaung. The Pagan Empire disintegrated and anarchy ensued. The Mongols, who probably preferred the situation, did nothing to restore order in the next ten years. In