The first signs of disorder appeared soon after Narathihapate's accession in 1256. The inexperienced king faced revolts in Arakanese state of Macchagiri (present-day Kyaukpyu District) in the west, and Martaban (Mottama) in the south. The Martaban rebellion was easily put down but Macchagiri required a second expedition before it too was put down. The calm did not last long. Martaban again revolted in 1285. This time, Pagan could not do anything to retake Martaban because it was facing an existential threat from the north. The Mongols of the Yuan dynasty demanded tribute, in 1271 and again in 1273. When Narathihapate refused both times, the Mongols under Kublai Khan systematically invaded the country. The first invasion in 1277 defeated the Burmese at the battle of Ngasaunggyan, and secured their hold of Kanngai (modern-day Yingjiang, Yunnan, north of Bhamo). In 1283–85, their forces moved south and occupied down to Hanlin. Instead of defending the country, the king fled Pagan for Lower Burma where he was assassinated by one of his sons in 1287.