First Contact between Goryeo and the Mongols

Timeline

1. 1224Gaeseong · GaeseongMongol envoy Zhugu Yu (Zhugu Yu) again reached the Goryeo capital Gaeseong via the Dongzhen route, demanding fulfillment of the pact's tribute obligations. His arrogant words and harsh demands provoked strong dissatisfaction at the Goryeo court and military regime, and Mongol-Goryeo relations rapidly shifted from cooperation to confrontation.
2. 1224Northeastern Korean Peninsula · northeastern frontierDongzhen's Puxian Wannu took advantage of the Mongol western campaigns to sever ties and rebel against the Mongols, sending envoys to Goryeo proposing a market for trade. Caught between Mongol suzerainty pressure and Dongzhen's geopolitical interests, Goryeo adopted a wait-and-see policy, maintaining limited contact with both sides as its diplomatic room shrank.
3. 1225Yalu River basin (Hamjinjin–Uiju line) · Yalu RiverZhugu Yu traveled north from Goryeo and was killed on the banks of the Yalu River near Hamjinjin en route through the Uiju area. Goryeo insisted it was not responsible, suspecting Jin or Dongzhen forces of framing them, but the Mongols still blamed Goryeo; in 1225 the two sides severed relations, setting the stage for the Mongols' first large-scale invasion of Goryeo in 1231.