Mongol Invasions of Korea (1231-1259): How Goryeo Resisted

The Mongol invasions of Korea were a series of campaigns between 1231 and 1259 in which the Mongol Empire attacked the Korean kingdom of Goryeo. Rather than surrender, Goryeo’s military rulers moved the royal court to Ganghwa Island and resisted for almost three decades while the mainland was devastated. The war ended with Goryeo accepting Mongol overlordship but keeping its own dynasty, an unusual outcome among the many states the Mongols attacked.

Background: Goryeo and the rise of the Mongols

Goryeo had ruled the Korean peninsula since the 10th century, as described in the article on the founding of the Goryeo dynasty. From 1170 real power lay with military officers rather than the kings, and from 1196 the Choe family ruled as hereditary military dictators while kings such as Gojong (r. 1213-1259) reigned in name.

Goryeo first met the Mongols in 1218-1219, when the two cooperated against Khitan rebels who had fled into Korea after the Mongol campaigns against the Jin dynasty of northern China. The alliance turned into heavy demands for tribute. In 1225 a Mongol envoy, Zhu Gu-yu, was killed on his way home from Goryeo. The Mongols blamed the Koreans, and once Ögedei had become Great Khan he had a pretext for war.

The first invasions (1231-1232)

In 1231 a Mongol army under the general Sartaq (Saritai) crossed the Yalu River. The fortress of Guju, defended by Pak Seo, held out against repeated assaults, including siege engines and fire attacks, but other Mongol columns advanced towards the capital Gaegyeong (modern Kaesong). The court agreed to terms early in 1232, paid tribute and accepted Mongol overseers, called darughachi, in the north-west.

The peace did not last. In mid-1232 the dictator Choe U decided to move the court and much of the capital’s population to Ganghwa Island, at the mouth of the Han River. The Mongols were formidable on land but had no fleet in the area, and the island’s narrow strait and strong tides made a crossing very difficult. Choe U ordered the people of the countryside to take refuge in mountain fortresses and on offshore islands.

The Mongols answered with a second invasion in 1232. It ended suddenly when Sartaq was killed by an arrow at the small fortress of Cheoin, near modern Yongin. Korean tradition credits the shot to the monk Kim Yun-hu, who refused a reward for it. The Mongol army withdrew.

Decades of war (1235-1259)

The third invasion, from 1235 to 1239, was the longest and most destructive so far. Mongol forces ranged across the peninsula, burning towns and temples. In 1238 they burned the great wooden pagoda of Hwangnyongsa in Gyeongju, built in the 7th century. The first Korean edition of the Buddhist scriptures, carved in woodblocks in the 11th century, had already been destroyed at Buinsa temple in 1232. In response the court began carving a new set, today’s Tripitaka Koreana, as an act of devotion and a prayer for protection.

Further campaigns followed in 1247-1248, interrupted by the death of the Great Khan Güyük, and in 1253, when Kim Yun-hu, now a commander, defended Chungju through a siege of about seventy days. The most terrible phase came after 1254 under the general Jalairtai. The official history of the dynasty, the Goryeosa, records that in 1254 alone 206,800 people were taken captive and that countless others were killed. Such figures cannot be checked precisely, but all sources agree that the suffering was enormous.

The Mongols repeatedly demanded that the king leave Ganghwa and return to the mainland as proof of submission. The Choe regime refused, because the island was the base of its power. Meanwhile peasants and local soldiers bore the brunt of the fighting, sometimes defending mountain fortresses with great courage, sometimes surrendering or rebelling against heavy taxes.

Peace and submission

The deadlock was broken by politics inside Goryeo. In 1258 Choe Ui, the last of the Choe dictators, was assassinated by the officer Kim Jun and others, and the civil officials and the king’s party pressed for peace. In 1259 Crown Prince Wang Jeon set out to submit in person. He met Kublai, who was then campaigning in China and would soon become Great Khan. King Gojong died the same year, and the prince returned to rule as King Wonjong (r. 1260-1274).

Kublai granted generous terms. Goryeo kept its dynasty, its territory south of the frontier zones, and its own customs. In return it became a vassal of the Mongols, paid tribute and later supplied ships and soldiers. The court moved back to Gaegyeong in 1270. Part of the military, the elite unit called the Sambyeolcho, refused to accept this and rebelled, holding out on Jindo and then Jeju islands until it was crushed in 1273 by a combined Goryeo and Mongol force.

Key people

• Gojong (1192-1259): King of Goryeo throughout the war, though real power lay with the Choe dictators.
• Choe U (died 1249): military dictator who moved the court to Ganghwa Island in 1232.
• Sartaq (Saritai): Mongol general who led the 1231 invasion and was killed in 1232.
• Kim Yun-hu: monk and soldier, hero of Cheoin (1232) and Chungju (1253).
• Wonjong (1219-1274): as crown prince, he negotiated the submission of 1259 with Kublai.

Consequences

For about eighty years after 1270, Goryeo was a “son-in-law nation” of the Mongol Yuan dynasty. Its kings married Mongol princesses, beginning with Chungnyeol, who married a daughter of Kublai in 1274, and they spent long periods at the Yuan court. Goryeo was obliged to build ships and provide troops for the Mongol invasions of Japan in 1274 and 1281, a heavy burden on an exhausted country.

Mongol influence also brought new contacts. Korean scholars travelled to Yuan China, and Neo-Confucian learning, which later shaped the Joseon dynasty, entered Korea in this period. Goryeo regained full independence under King Gongmin in the 1350s as the Yuan dynasty weakened.

Life during the war

On Ganghwa Island the court tried to carry on as normal. It built palaces and walls, held Buddhist ceremonies and examinations, and lived on taxes shipped by sea from the southern provinces, which the Mongols reached less often. Grain barges along the coast kept the island supplied, and the court’s control of the sea was one of its greatest advantages.

For people on the mainland, life was far harder. Villagers were ordered to abandon the lowlands for mountain fortresses and islands, often leaving their fields untended. Some local communities fought bravely: slaves and commoners helped defend fortresses such as Chungju, and in some cases they were rewarded with freedom or rank. In other places, exhausted by war and taxes, local officials and people went over to the Mongols. Some northern districts that surrendered were later organised by the Mongols as separate commanderies, and parts of the north-east remained under direct Mongol control until the 1350s.

Historians still debate the Choe regime’s strategy. Some see the retreat to Ganghwa as a heroic act of resistance that preserved Korea’s independence; others argue that it protected the dictators’ power while leaving the population to suffer.

Timeline

• 1218-1219: Goryeo and Mongol forces cooperate against Khitan invaders.
• 1225: The Mongol envoy Zhu Gu-yu is killed after leaving Goryeo.
• 1231: Sartaq invades; the siege of Guju begins.
• 1232: The court moves to Ganghwa Island; Sartaq is killed at Cheoin.
• 1235-1239: Third invasion; Hwangnyongsa pagoda burned in 1238.
• 1253: Kim Yun-hu defends Chungju against a long siege.
• 1254: Jalairtai’s campaign; the Goryeosa records 206,800 captives.
• 1258: Choe Ui is assassinated, ending the Choe dictatorship.
• 1259: Crown Prince Wang Jeon submits to the Mongols; King Gojong dies.
• 1270-1273: The court returns to Gaegyeong; the Sambyeolcho rebellion is suppressed.

Why it matters

Goryeo’s long resistance showed how geography and determination could frustrate the most powerful army of the age, even if it could not ultimately defeat it. The war devastated Korea but left its state and culture intact, and it produced lasting monuments of faith and national memory, from the Tripitaka Koreana to the stories of Kim Yun-hu.