text:  The Mongols first demanded tribute from Pagan in 1271 – 72 , as part of their drive to encircle the Song dynasty of China . When King <unk> 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 – 85 ) later , the Mongols had occupied down to <unk> and Hanlin , forcing the Burmese king to flee to Lower Burma . The Mongols organized northern Burma as the province of <unk> . 
  