Mongol invasions of Korea

Between 1231 and 1259 the armies of the Mongol Empire invaded the Korean kingdom of Goryeo again and again, in a series of campaigns usually counted as nine. Goryeo's military rulers withdrew the court to Ganghwa Island and ordered the population into mountain fortresses and onto islands, a strategy that prevented outright conquest but left the country devastated. The wars ended with a peace that made Goryeo a vassal of the Mongol Yuan dynasty for some eighty years.

Goryeo first met the Mongols during the turmoil that followed their attacks on the Jurchen Jin dynasty. In 1216 Khitan rebels fleeing the Mongols crossed the Yalu River and ravaged northern Korea. In the winter of 1218 a Mongol and Jurchen army entered Goryeo to pursue them, and with Korean help it forced the last Khitan stronghold, Kangdong, to surrender in early 1219. The Mongols then demanded annual tribute. Relations soured, and they broke off contact in 1225 after a Mongol envoy was murdered on his way home, a killing they blamed on Goryeo.

On 26 August 1231 a Mongol army under Saritai crossed the Yalu. Some commanders surrendered, but others resisted fiercely; the fortress of Kuju held out for months against catapults, siege towers and mines. After the main Korean army was defeated and Kaesong, the capital, was surrounded, Goryeo submitted. Saritai demanded huge quantities of horses, cloth and otter skins and left 72 officials to supervise the northwest.

The military dictator Ch'oe U then moved the king and court to Ganghwa Island in 1232, and the Mongol overseers on the mainland were killed. Saritai invaded again, but at Ch'ŏin he was shot dead by an arrow loosed by the monk Kim Yun-hu, and his army withdrew.

In 1235, after the Mongols had destroyed the Jin, the great khan Ögedei ordered a new attack. For four years Mongol troops ranged as far south as present-day Seoul. Goryeo no longer risked large field armies. Instead it relied on small mobile units and on fortified refuges, and the Mongols never took Ganghwa itself. During this invasion the king ordered new printing blocks for the Buddhist scriptures, the Tripitaka Koreana, completed in 1248. A truce followed, in which Goryeo sent a royal relative passed off as the crown prince as a hostage.

Further invasions came in 1247, 1253 and nearly every year afterwards, as the Mongols demanded that the king leave Ganghwa and come to their court. In 1253 Chungju held out through a 70-day siege, and in 1254 the Mongols reportedly lost half their force before a mountain fortress at Sangju. Yet the 1254–1255 campaign alone is said to have carried off some 206,800 captives, and famine spread so widely that corpses lined the roads.

In 1258 the last Ch'oe dictator was murdered and power returned to the king. People in the northeast rebelled and went over to the Mongols, who set up a prefecture there. In the spring of 1259 Goryeo agreed to send the crown prince, the future King Wonjong, to the Mongol court and to return the capital to the mainland. Kublai Khan welcomed the prince's submission with delight. Some military units, the Sambyeolcho, rebelled against the settlement from 1270 to 1273.

For about eighty years Goryeo was a subordinate ally of the Yuan dynasty, its kings marrying into the Mongol imperial family. The wars had destroyed much of the country's heritage, including the nine-storey pagoda of Hwangnyongsa and the first set of Tripitaka blocks. Only in the 1350s, as Yuan power crumbled, did Goryeo push back the Mongol garrisons.

Our 1200 map shows Goryeo before the invasions, and the 1279 map shows the Korean peninsula under Mongol overlordship, in the lands that are now South Korea and North Korea.