Mongol invasions of Korea

A series of campaigns were conducted between 1231 and 1270 by the Mongol Empire against the Goryeo dynasty of Korea. There were seven major campaigns at tremendous cost to civilian lives, the last campaign made most of Goryeo a vassal state of the Yuan dynasty for approximately 80 years. However, rebellion movements existed throughout this time and in 1274, some Goryeo territory existed outside of Mongol control.

The Yuan dynasty would exact wealth and tributes from the Goryeo kings. Despite submission to the Yuan dynasty, internal struggles among Goryeo royalty and rebellions against Yuan rule would continue, the most famous being the Sambyeolcho Rebellion. A greater amount of "stubborn resistance" was put up by Korea and Song Dynasty towards the Mongol invasions than many others in Eurasia who were swiftly crushed by the Mongols at a lightning pace.

Khitan invasion (1216 – 1219)
Goryeo first encountered the Mongols in 1211 when a Goryeo envoy to the Jin dynasty (1115–1234) was killed by Mongol soldiers.

Later the Mongols entered Goryeo while pursuing enemy Khitans. In 1211, the Khitan prince Yelü Liuge who had been serving the Jin as a military commander rebelled and seized a portion of Liaodong. Two years later he proclaimed himself the ruler of the Liao. Yelü Liuge was ousted by his younger brother, Yelü Sibu, and requested help from Genghis Khan against the usurper. Sibu was also usurped by one of his ministers, Yelü Qinu. In 1214, the Jin assigned Puxian Wannu to suppress the rebellion. However Puxian Wannu was defeated and he himself rebelled in 1215. Based in Dongjing ("Eastern Capital"), Puxian Wannu declared the state of Dazhen ("Great Jurchen"). In the spring of 1216, Khitans fleeing from the Jin overran Puxian Wannu's territory and held the area from Dengzhou to Poju (Uiju).

In 1216, the Mongols accompanied by Yelü Liuge chased the Khitan rebels to the Goryeo borders and launched an attack on Dafuying, located on an island in the lower course of the Yalu River. The Khitans requested help from Goryeo but when the request was denied, the Khitans crossed the Yalu with an estimated 90,000 men and overran the Goryeo frontier. The Khitan rebels spent 1217 pillaging southwards down the Korean peninsula before several defeats at the hand of Korean General Kim Ch'wiryŏ forced them to retreat. They turned their attention back toward the territory of Puxian Wannu. Puxian Wannu had already been defeated by the Mongols and submitted, but when the Mongol forces withdrew, he moved further east toward the Yalu and in early 1217, declared the state of Dongxia ("Eastern Xia"). Pressured by the Jin, he fled eastward again to the lower reaches of the Tumen River. It was also there that the Khitans fled from Goryeo. The Khitans were able to gather reinforcements and then invaded Goryeo again in the fall of 1217. The Khitan invasion was halted after they took the city of Kangdong, where Goryeo forces managed to contain them.

In the winter of 1218, 10,000 Mongol troops commanded by Hazhen and Zhala accompanied by 20,000 Eastern Jurchen troops commanded by Wanyan Ziyuan entered Goryeo from the northeast. They defeated Khitan forces in the cities of Hwaju, Maengju, Sunju, and Tŏkchu. The Mongol-Jurchen advance was stopped by a heavy snowfall that made the roads impassable. Hazhen sent a letter carried by the translator Zhao Zhongxiang to Cho Ch'ung, the Goryeo commander in charge of the northwest, requesting provisions and demanding the two nations enter an Elder-Younger Brother relationship after the subjugation of the Khitans.

Cho Ch'ung and Kim Ch'wiryŏ were in favor of meeting the Mongol demands but the Goryeo court was more apprehensive. Ultimately they agreed to provide for the Mongol forces at the urging of Cho. One thousand bushels of rice and one thousand picked troops were sent to the Mongols. They arrived in time to witness the Mongols assault the Khitans in the walled-city of Taeju. The reinforcements were received well by the Mongols.

In early 1219, preparations were underway to take the last Khitan stronghold in Kangdong. Troops from Goryeo joined the Mongol-Jurchen force. An estimated 50,000 Khitans surrendered and opened the gates.

After the fall of Kangdong, Goryeo sent a delegation to Zhala's camp as well as gifts to the Mongol commanders. Mongol envoys met with Gojong of Goryeo (reigned 1213–1259) and handed him a document without the usual formalities. Cho accompanied the Mongol and Jurchen commanders to the Yalu where the Mongols seized a large number of Goryeo horses and left. However they left behind 41 subordinates in Poju to learn the language of Goryeo and to wait for the Mongols' return. The Mongols also started collecting annual tribute from Goryeo and within two years, Gojong was advocating for the cessation of tribute payments and resistance against the Mongols.

Conditions in the northwest were poor following the Khitan raids. In the autumn of 1219, military commanders Han Sun and Ta Chi rebelled in Poju and defected to Puxian Wannu, who augmented their forces with 10,000 Eastern Jurchens. They tried to make an alliance with the Jin commander Yugexia. Yugexia invited them to a feast and killed them. Their heads were sent to Kaesong in early 1220 for which Yugexia was rewarded greatly by the Goryeo court. However Yugexia repeatedly sacked Goryeo's border cities for several years afterward. Troops sent to Poju to restore order slew so many that another rebellion occurred four months later that required 5,000 troops to put down. Khitans who had fled into the mountains continued to raid Goryeo garrisons.

First Mongol invasion of Korea (August 1231 – January 1232)
In 1221, a Mongol delegation led by Zhuguyu made a list of demands while 6,000-7,000 Mongol troops arrived at the Goryeo border a few days later. They were received coldly by the Goryeo court. In 1224, Puxian Wannu declared independence from the Mongols and sent envoys to Goryeo to establish an alliance. Goryeo rejected the offer and over the next four years, Eastern Jurchens raided Goryeo. An attempt at peace negotiations was made in 1229 due to deteriorating relations between the Mongols and Goryeo.

A Mongol delegation led by Zhuguyu had arrived in 1224 to supervise the transfer of tribute. They took only the otter pelts but discarded the other items in the fields while crossing the Yalu. During their journey they were killed by bandits. Since the Mongols suspected Goryeo, relations had been terminated in early 1225. When the Mongols ordered Goryeo to attack Puxian Wannu, Goryeo did not comply.

On 26 August 1231, a Mongol force led by Saritai crossed the Yalu and surrounded Hamsin-chin (Uiju). Defense General Cho Sukch'ang and Deputy Commissioner Chŏn Kan surrendered Hamsin-chin to the Mongols. The Mongol forces split with one group heading north to attack Sakju while the other group headed down the Yalu. When the second group heading south reached Chongju, Kim Kyŏngson at first tried to fight the Mongols but the entire city had already fled, so he retreated to Kuju Castle. From Chongju, the Mongols proceeded to Inju where Hong Pok-wŏn defected and submitted the area and 1,500 households. His family later played a pivotal role in the Mongol campaigns against Goryeo by acting as guides. At Ch'ŏlchu (in Hamgyong Province), the men slit their throats and burned the granary and all the women and children rather than submit to the Mongols.Yongju, Sonju, and Kwakchu fell in October.

The Mongols bypassed Chaju and the Western Capital (Pyongyang) where they encountered stiff resistance. The slave army led by Ji Gwang-su fought to the death. They took Hwangju before reaching Chabi Pass, the gateway to Kaesong.

Ch'oe U called up the Three Armies and levied troops from the provinces. Yugexia contributed 5,000 soldiers and even bandits entered the Goryeo army. The Three Armies under the leadership of Yi Chasŏng departed Kaesong in early October and fended off a surprise attack by 8,000 Mongol soldiers. The Goryeo army was defeated at Anju, after which Goryeo started negotiations with the Mongols. However, when news that the Mongols demanded Goryeo's submission reached the court in late November, the Goryeo response was to continue resistance. Kaesong was surrounded by Mongol forces in late December. Goryeo officially submitted and the Three Armies surrendered.

Goryeo's surrender did not mean an immediate end to the fighting. The Mongols sacked cities which they had previously taken. Chŏn Kan attempted to kill the Mongols in Hamsin-chin but a certain Xiaoweisheng escaped. Chaju held out while heavy fighting occurred at Chongju. At the Siege of Kuju, Pak Sŏ led forces who had gathered from surrounding cities in a defense against the Mongols. Kim Chungon defended the eastern and western walls while Kim Kyŏngson defended the south. The Mongols attacked the west, south, and north gates repeatedly. They used carts of grass and wood as well as towers to try to scale the walls but the defenders countered with molten iron, setting fire to the siege machines. They also tried to mine the city walls but the tunnel collapsed. The south wall was attacked by 15 large catapults. The defenders used their own catapults to drive off the attackers while using mud and water to put out fires by inflammatory projectiles. The Mongols withdrew for a time after 40 days of besieging the city only to return with reinforcements. They set up 30 catapults and breached the city wall in 50 places but they were repaired while Pak Sŏ made a successful sortie and drove off the attackers. Kuju and Chaju finally submitted after multiple orders from the Goryeo court. Pak Sŏ and Ch'oe Ch'unmyŏmg, defender of Chaju, were almost executed but the Mongols spared them owing to their courage, which they admired.

Saritai demanded 10,000 small horses, 10,000 large horses, 10,000 bolts of purple gauze, 20,000 otter skins, and clothing for a million men army. Hostages from the king's family, provincial leaders, and high officials were also demanded. A large tribute was presented by Goryeo but no hostages. General Saritai began withdrawing his main force to the north in the spring of 1232, leaving 72 Mongol administrative officials (Darughachi) stationed in various cities in northwestern Goryeo to ensure that Goryeo kept to the peace terms. They controlled almost all of modern North Pyongan Province and a great portion of South Pyongan Province as well.

Second Mongol invasion of Korea (June 1232 – December 1232)


When the Mongols threatened Kaesong in the previous invasion, Ch'oe U sent his family to Ganghwa Island. In the spring of 1232, Ch'oe U gathered all the high officials at his residence and suggested transferring the capital to Ganghwa. A dissenter, Kim Sech'ung, was executed for speaking out against the plan. The royal family relocated to Ganghwa and commissioners were sent out to the provinces to instruct the people to take refuge in mountain citadels or coastal islands. With the transfer complete, in the summer of 1232, the Mongol darughachi on the mainland were killed.

The Western Capital (Pyongyang) was still under the control of Hong Pok-wŏn, a Goryeo warlord who had defected to the Mongols. When the people of the Western Capital learned that the court was planning on killing the Mongol officials, they rebelled out of fear that Mongol reprisal would result in their deaths. Government officials in the Western Capital fled to Chŏ Island.

In the summer of 1232, the Mongol invasion led by Saritai advanced south into the Han valley without much resistance. However in an attack on Ch'ŏin-song, Saritai was killed by an arrow shot by the monk Kim Yun-hu. The Mongol army retreated, leaving Hong Pok-wŏn to supervise the territory that they had conquered.

In the spring of 1233, a Mongol envoy delivered a list detailing Goryeo's crimes. The Goryeo response was an offensive against Hong Pok-wŏn to oust him from the Western Capital. Hong escaped with his family to Mongol territory in Liaoyang and Shenyang while the Western Capital's people were resettled in island locations. The Mongols appointed Hong as leader of northwestern Goryeo.

Third Mongol invasion of Korea and treaty (July 1235 – April 1239)
By late 1233, Güyük and Prince Alchidai had defeated Puxian Wannu and in early 1234, conquered the Jin dynasty. In the kurultai of 1235, Ögedei Khan gave orders to attack Goryeo, Southern Song, the people west of the Volga, and to push to the edge of Kashmir.

In the summer of 1235, Mongol troops raided Goryeo. Defenses were put up around Ganghwa Island and the people of the Southern Capital (modern Seoul) and Gwangju were ordered to evacuate to the island. By late 1235, Mongol and Eastern Jurchen troops under the command of Tanqut-Batur had taken Yonggang, Hamjong, Samdŭng, and Haep'yong (modern Sangju). In the spring of 1236, Mongol troops moved south and took Hwangju, Sinju, and Anju. By wintertime, the Mongols had reached as far south as the Southern Capital and penetrated Cheongju.

Goryeo did not attempt to field an army against the Mongols and offensive actions were limited to raids against small patrols. The people were told to evacuate to defensible locations such as mountain fortresses or island strongholds and left to fend for themselves. Ganghwa Island itself was heavily defended and the Mongols never attempted to take it. During the invasion, King Gojong ordered a set of printing blocks for the Buddhist canon to be created and work began in 1237. The Goryeo Daejanggyeong was completed in 1248.

Some people in Goryeo defected to the Mongols. In the summer of 1238, 2,000 men under the leadership of Cho Hyŏnsŭp and Yi Wŏnu submitted to the Mongols. Cho was put under the command of Hong Pok-wŏn. A Yi Kunsik also defected with 12 people.

Negotiations were opened in the winter of 1238 with Goryeo promising eternal submission, after which the Mongols withdrew. The Mongol envoys brought a list of demands that included that the king of Goryeo present himself at the Mongol court. Goryeo's Queen Dowager had just passed away and the king used the mourning period as an excuse to avoid compliance. Many more excuses were given later including illness and that he was too advanced in his age. Goryeo sent as a hostage Chŏn, the Duke of Sinan, and passed him off as the king's brother. He went to the Mongol court with a retinue of 148 men to present a petition and tribute. A royal relative, Wang Sun, the Duke of Yŏngnyŏng, was also sent as a hostage to the Mongol court while pretending to be the crown prince. The arrival of the 17-year old pretend prince at the Mongol court in 1241 and the resumption of tribute missions secured a moment of respite for Goryeo until 1247.

Goryeo's capital was not relocated back to the mainland despite Mongol demands. Gojong did meet Mongol envoys on the mainland a few years later, but Ch'oe U and his successors, the ones responsible for defending Goryeo, remained on the island for the rest of their lives. The momentary peace was used to send messages to southern Goryeo with instructions to prepare the defenses. Goryeo's continued resistance resulted in another Mongol invasion in 1247.

Fourth Mongol invasion of Korea (July 1247 – March 1248)
In the fall of 1247, a Mongol force commanded by Amukan and a supporting force led by Hong Pok-wŏn arrived in Yŏmju (modern Yonan County). The Mongols controlled the area north of the Chongchon River and raided Goryeo. After Güyük Khan died in 1248, the royal hostage Wang Chŏn returned to Goryeo.

Fifth Mongol invasion of Korea (July 1253 – January 1254)
Upon the 1251 ascension of Möngke Khan, the Mongols again repeated their demands. Möngke Khan sent envoys to Goryeo, announcing his coronation in October 1251. He also demanded the King Gojong be summoned before him in person and his headquarters be moved from Ganghwa Island to the Korean mainland. But the Goryeo court refused to send the king because the old king was unable to travel so far. Möngke again dispatched his envoys with specific tasks. The envoys were well received by the Goryeo officials but they also criticized them, saying their king did not follow his overlord Möngke's orders. Möngke ordered the prince Yeku to command the army against Korea. However, a Korean in the court of Möngke convinced them to begin their campaign in July 1253. Yeku, along with Amuqan, demanded the Goryeo court to surrender. The court refused but did not resist the Mongols and gathered the peasantry into the mountain fortresses and islands. Working together with the Goryeo commanders who had joined the Mongols, Jalairtai Qorchi ravaged Korea. When one of Yeku's envoys arrived, Gojong personally met him at his new palace in Sin Chuan-bug. Gojong finally agreed to move the capital back to the mainland, and sent his stepson Angyeong as a hostage. The Mongols agreed to a cease fire in January 1254.

Sixth Mongol invasion of Korea (July 1254 – December 1254)
The Mongols later learned that top Goryeo officials remained on Ganghwa Island, and had punished those who negotiated with the Mongols. Between 1253 and 1258, the Mongols under Jalairtai launched four devastating invasions in the final successful campaign against Korea.

Möngke realized that the hostage was not the blood prince of the Goryeo Dynasty. So Möngke blamed the Goryeo court for deceiving him and killing the family of Lee Hyeong, who was a pro-Mongol Korean general. Möngke's commander Jalairtai devastated much of Goryeo and took 206,800 captives in 1254. Famine and despair forced peasants to surrender to the Mongols. They established a chiliarchy office at Yonghung with local officials.

Seventh Mongol invasion of Korea (September 1255 – June 1256)
Ordering defectors to build ships, the Mongols began attacking the coastal islands from 1255 onward. In the Liaodong Peninsula, the Mongols eventually massed Korean defectors into a colony of 5,000 households.

Mongke Khan once again sent a large army along with Prince Yeongnyeong and Hong Pok-wŏn, who had been taken hostage by Jalaltai as the captain, and gathered at Gapgot Daedan (甲串岸) and showed momentum to attack Ganghwa Island. However, Kim Sugang (金守剛), who had just gone to Mongolia, succeeded in persuading Mongke Khan, and the Mongols withdrew from Goryeo.

Eighth Mongol invasion of Korea (May 1257 – October 1257)
In 1258, Goryeo's King Gojong and one of the retainers of the Ch'oe clan, Kim Injoon, staged a counter-coup and assassinated the head of the Ch'oe family, ending the rule of the Ch'oe family which spanned six decades. Afterwards, the king sued for peace with the Mongols. When the Goryeo court sent the future king Wonjong as hostage to the Mongol court and promised to return to Kaegyong, the Mongols withdrew from Central Korea.

There were two parties within Goryeo: the literati party, which opposed the war with the Mongols, and the military junta—led by the Ch'oe clan—which pressed for continuing the war. When the dictator Ch'oe was murdered by the literati party, the peace treaty was concluded. The treaty permitted the maintenance of the sovereign power and traditional culture of Goryeo, implying that the Mongols gave up incorporating Goryeo under direct Mongolian control and were content to give Goryeo autonomy, but the king of Goryeo must marry a Mongolian princess and be subordinate to the Mongolian Khans.

Ninth Mongol invasion of Korea
The Mongols invaded Korea a ninth time in 1257.

Aftermath
Much of Goryeo was devastated after the decades of fighting. It was said that no wooden structures remained afterward in Goryeo. There was cultural destruction, and the nine-floor-tower of Hwangnyongsa and the first Tripitaka Koreana were destroyed. After seeing the Goryeo crown prince come to concede, Kublai Khan was jubilant and said "Goryeo is a country that long ago even Tang Taizong personally campaigned against but was unable to defeat, but now the crown prince comes to me, it is the will of heaven!"

Internal struggles within the royal court continued regarding the peace with the Mongols until 1270.

Since Ch'oe Ch'ung-hŏn, Goryeo had been a military dictatorship, ruled by the private army of the powerful Ch'oe family. Some of these military officials formed the Sambyeolcho Rebellion (1270–1273) and resisted in the islands off the southern shore of the Korean peninsula.

Beginning with Wonjong, for approximately 80 years, Goryeo was a vassal state and compulsory ally of the Yuan dynasty. The Mongol and Korean rulers were also tied by marriages as some Mongol prince and aristocrats married Korean princesses and vice versa. During the reign of Kublai Khan, King Chungnyeol of Goryeo married one of Kublai's daughters. Later, a Korean princess called the Empress Gi became an empress through her marriage with Toghon Temür, and her son, Ayushiridara became an emperor of the Northern Yuan dynasty. The Kings of Goryeo held an important status like other important families of Mardin, Uyghurs and Mongols (Oirat, Hongirat, and Ikeres). It is claimed that one of Goryeo monarchs was the most beloved grandson of Kublai Khan and had grown up at the Yuan court.

The Mongol darughachis at the court of the Goryeo were offered provisions and sometimes were also willing to actively be involved in the affairs of the Goryeo court. Even today, there are several Mongolian words used in the Jeju Island. Furthermore, the Mongol domination of Eurasia encouraged cultural exchange, and this would include for example the transmission of some of the Korean ideas and technology to other areas under Mongol control.

The Goryeo dynasty survived under influence of the Yuan dynasty until it began to force Yuan garrisons back starting in the 1350s, when the Yuan dynasty was already beginning to crumble, suffering from massive rebellions in China. Taking advantage of the opportunity, the Goryeo army under Goryeo king Gongmin also managed to regain some northern territories. Empress Gi sent the Mongol army to invade Goryeo in 1364, but it failed.