The first Mongol invasions of Burma ( Myanmar ) ( Burmese : မွန ် ဂို – မြန ် မာ စစ ် ( ၁၂၇၇ – ၁၂၈၇ ) ) were a series of military conflicts between Kublai Khan 's Yuan dynasty , division of the Mongol Empire , and the Pagan Empire that 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 Tai @-@ Shan states throughout mainland Southeast Asia .