Later Three Kingdoms period and the War for Unification From 889 to 935 AD, the
Unified Shilla began to decline from corruption and internal strife, which led to the revival of
Later Baekje and
Later Goguryeo. A monk named
Kung Ye founded
Hugoguryeo but changed the names to Majin and Taebong in later years. Taejo's father,
Wang Yung (later posthumously given the
temple name of Sejo of Goryeo), along with many local clans, quickly surrendered to Kung Ye. Wang Kŏn followed his father into service under
Kung Ye, the future leader of
Taebong, and he began his service under Kung Ye's command. In 900, he led a successful campaign against local clans and the army of
Later Baekje in the
Chungju area, gaining more fame and recognition from the king. In 903, he led a famous naval campaign against the southwestern coastline of Later Baekje (Keumsung, later Naju) while
Kyŏn Hwŏn was at war against Silla. He led several more military campaigns and helped conquered people living in poverty under Silla's rule. The public favored him due to his leadership and generosity. He also led Taebong's Navy, took Geumseong from the Later Baekje, renamed it Naju, and stationed the troops in 903. In 909, Wang Kon became Admiral of the Navy and led the naval forces. Kyŏn Hwŏn captured the envoy's ship from Yeomhae County within the jurisdiction of Gwangju. That year, Wang Kon captured
Jindo and Koido (皐夷島) of the Later Baekje with 2,500 soldiers. The following year, when Kyŏn Hwŏn threatened Naju again, Wang Kŏn defeated Kyŏn Hwŏn's naval forces at the Naju port, and arrived at the port of Bannamhyeon (潘南縣), captured the pirate leader Neungchang, and sent it to Gungye to behead him. This would be Wang Kon's naval military activity before the founding of Goryeo and, at the same time, Taebong's maritime activity. However, Kung Ye began to refer to himself as the Buddha and persecuted people who expressed their opposition to his religious arguments. He executed many monks, then later, even his wife and two sons, and the public began to turn away from him. His costly rituals and harsh rule caused even more opposition. In 918, four of his generals—
Hong Yu,
Pae Hyŏn-gyŏng,
Sin Sung-gyŏm and
Pok Chigyŏm—overthrew Taebong and installed Wang Kon as King Taejo. In 927, Kyŏn Hwŏn of Later Baekje led forces into Silla's capital,
Gyeongju, capturing and executing its king,
King Gyeongae. Then he established King Gyeongsun as his puppet monarch before he turned his army toward Goryeo. Hearing of the news, Taejo planned a strike with 5,000 cavalrymen to attack Kyŏn's troops on the way back home at Gongsan near
Daegu. He met Later Baekje forces and suffered a disastrous defeat, losing most of his army, including his generals
Kim Nak and Sin Sung-gyŏm, the very same man who crowned Wang as a king. However, Goryeo quickly recovered from defeat and successfully defended Later Baekje's attack on its front. In 935, the last king of Silla, King Gyeongsun, felt there was no way to revive his kingdom and surrendered his entire land to Taejo. Taejo gladly accepted his surrender and gave him the title of prince, and accepted his daughter as one of his wives (Wang had six queens and many more wives as he married daughters of every single local leader). It caused much disgust to Kyŏn Hwŏn. Kyŏn's father, who held his claim to the
Sangju region, also defected and surrendered to Goryeo and was received as the father of a king. Kyŏn Hwŏn's oldest son,
Kyŏn Sin-gŏm, led a coup with his brothers Yang-gŏm and Yong-gŏm, against their father, who favored their half-brother, Kŭm-gang, as his successor to the throne. Kyŏn Hwŏn was sent into exile and imprisoned in
Geumsansa but escaped to Goryeo and was treated like Taejo's father, who died just before his surrender. In 936, Wang led his final campaign against Kyŏn Sin-gŏm of Later Baekje. Kyŏn Sin-gŏm fought against Taejo, but facing many disadvantages and inner conflict, he surrendered to Taejo. Wang finally occupied Later Baekje formally and unified the nation for the second time since
Unified Silla; he ruled until 943. Taejo proposed to Gaozu of
Later Jìn that they attack the Khitans as revenge for the destruction of Balhae, according to the
Zizhi Tongjian. Furthermore, in his Ten Injunctions to his descendants, he stated that the Khitans are no different from beasts and should be guarded against. Negotiations began between the Goryeo commander,
Sŏ Hŭi, and the Liao commander, Xiao Sunning. In conclusion, Goryeo entered a nominal tributary relationship with Liao, severing relations with
Song, and Liao conceded the land east of the Yalu River to Goryeo. In 994, Goryeo proposed to Song a joint military attack on Liao, but was declined; previously, in 985, when Song had proposed a joint military attack on Liao, Goryeo had declined. For a time, Goryeo and Liao enjoyed an amicable relationship. with a promise that he would pay homage in person to the Liao emperor, and the Khitans, who were sustaining attacks by the regrouped Korean army and disrupted supply lines, accepted and began their withdrawal. According to the
History of Liao, the Khitans were beset by heavy rains and discarded much of their armor and weapons. Afterward, Hyeonjong did not fulfill his promise to pay homage in person to the Liao emperor, and when demanded to cede the Six Garrison Settlements, he refused. The Liao army pushed on toward Kaesong under constant enemy harassment, but shortly turned around and retreated after failing to take the well-defended capital. The Jurchens north of Goryeo had traditionally rendered tribute to the Goryeo monarchs and called Goryeo their "parent country" considering past ties between
Goguryeo and its
Mohe subjects, but thanks to the defeat of Liao to the Koreans in 1019, the
Wanyan tribe of the
Heishui Mohe unified the Jurchen tribes and gained in might, taking advantage of the power vacuum. At the peak of its power, Goryeo contested with the rising
Wanyan tribes of which Goryeo considered them as barbaric vassals descending from the
Mohe people that served their
Goguryeo ancestors, in the state of total war over former territories of Goguryeo and
Balhae. As the geopolitical situation began to shift in turbulence by the start of the 12th century, Goryeo unleashed two major military campaigns from 1104 to 1109 spearheaded by the ambitious
King Yejong with vows of reclaiming former
Goguryeo territories held by Jurchen tribes united under the progenitors of the Jin dynasty,
Wanyan Wuyashu and
Aguda, with the aims of also preventing potential aggressions from the Jurchen tribes. Led by prominent generals such as
Yun Kwan and
Ch'ŏk Chun-gyŏng, the well-trained
Byeolmuban (別武班; "Special Warfare Army") of approximately 250,000 men initially succeeded in ravaging Jurchen territories and building the strategic "Nine Fortresses" (동북 9성, 東北九城) of which exact locations are still topics of debate. Following the invasion, numerous Jurchen tribes surrendered to the invading Korean forces but many stayed vigilant and resumed fierce resistance led by the Wanyan tribe, complicating the phase of the war. Despite the Koreans of Goryeo having proceeded to utilizing
scorched earth tactics, the Jurchen tribes under the leadership of Wanyan Wuyashu achieved a pyrrhic victory as Goryeo considered securing the Nine Fortresses too costly albeit having the upper hand in the war. Contacted by the Jurchens of the Wanyan tribe that have tasted the bitterness as well of facing Korean forces in their homes for peace, Goryeo would eventually move on to reluctantly signing a peace agreement with the Wanyan tribe and later on ceded the Nine Fortresses to Wuyashu. Though the objective of reclaiming former ancestral lands failed, Goryeo managed to maintain peaceful relations with the Jin dynasty which progress in conquering the Liao and
Northern Song dynasty respectively. During the reign of Jurchen leader
Wuyashu in 1103–1113, the border between the two nations was stabilized and Korean forces withdrew from Jurchen territories, acknowledging Jurchen control over the contested region. In 1115 the Jurchen founded the
Jin dynasty, and in 1125 Jin annihilated Liao, which was Goryeo's suzerain, and started
invasion of Song. In response to the circumstantial changes, Goryeo declared itself to be a tributary state of Jin in 1126. After that, peace was maintained and Jin never actually did invade Goryeo.
Military regime Although the military founded Goryeo, its authority was in decline. In 1014, a coup occurred, but the effects of the rebellion didn't last long, only making generals discontent with the current supremacy of the civilian officers. In addition, under the reign of
King Uijong, military officers were prohibited from entering the Security Council, and even at times of state emergency, they were not allowed to assume commands. After political chaos, Uijong started to enjoy traveling to local temples and studying
sutra, while a large group of civilian officers almost always accompanied him. The military officers were largely ignored and mobilized to construct temples and ponds. In 1170, a group of army officers led by
Chŏng Chung-bu,
Yi Ŭi-bang and
Yi Ko launched a
coup d'état and succeeded.
King Uijong went into exile, and
King Myeongjong was placed on the throne beginning its military rule. In 1179, the young general
Kyŏng Tae-sŭng rose to power and began attempting to restore the monarch's full power and purge the state's corruption with his elite guard unit known as the
Tobang. However, he died in 1183 and was succeeded by
Yi Ŭi-min, who came from a
nobi (enslaved person) background. His unrestrained corruption and cruelty Ch'oe Ch'ung-hŏn was succeeded in turn by his son
Ch'oe U, his grandson
Ch'oe Hang and his great-grandson
Ch'oe Ŭi. Ch'oe Ch'ung-hŏn forced Myeongjong off the throne and replaced him with
King Sinjong. What was different from former military leaders was the active involvement of scholars in Ch'oe's control, notably Prime Minister
Yi Kyu-bo, who was a Confucian scholar-official. where the remaining Khitans were finished off by allied Mongol-Goryeo forces in 1219. Tension continued through the 12th century and into the 13th century when the
Mongol invasions started. During the House of Ch'oe's military rule, Goryeo resisted
invasions by the Mongol Empire for nearly 30 years until swearing allegiance to the Mongols, with the direct dynastic rule of Goryeo monarchy. The royal court moved to Ganghwado in the Bay of Gyeonggi in 1232. The military ruler of the time,
Ch'oe U, insisted on fighting back. Goryeo resisted for about 30 years but finally sued for peace in 1259. Meanwhile, the Mongols began a campaign from 1231 to 1259 that ravaged parts of
Gyeongsang and
Jeolla. There were six significant campaigns: 1231, 1232, 1235, 1238, 1247, and 1253; between 1253 and 1258, the Mongols under
Möngke Khan's general
Jalairtai Qorchi launched four devastating invasions against Korea at tremendous cost to civilian lives throughout the Korean peninsula. Civilian resistance was strong, and the Imperial Court at Ganghwa attempted to strengthen its fortress. Korea won several victories, but the Korean military could not withstand the waves of invasions. The repeated Mongol attacks caused havoc, loss of human lives, and famine in Korea. In 1236, Gojong ordered the recreation of the
Tripitaka Koreana, which was destroyed during the 1232 invasion. This collection of Buddhist scriptures took 15 years to carve on 81,000 wooden blocks and is still preserved. In March 1258, the dictator
Ch'oe Ŭi was assassinated by
Kim Chun after which authority was restored to the monarchy and peace was made with the
Mongols; however, power struggles continued in the court, and military rule did not end until 1270. Thus, dictatorship by his military group was ended, and the scholars who had insisted on peace with Mongolia gained power. Goryeo was never conquered by the Mongols, but exhausted after decades of fighting, Goryeo sent Crown Prince
Wonjong to the
Yuan capital to swear allegiance to the Mongols;
Kublai Khan accepted, and married one of his daughters to the Korean crown prince. Kublai, who became khan of the Mongols and emperor of China in 1260, did not impose direct rule over most of Goryeo. In contrast to Song China, Goryeo Korea was treated more like an Inner Asian power. The dynasty was allowed to survive, and intermarriage with Mongols was encouraged, even with the Mongol imperial family. At the same time, marriage between the Chinese and Mongols was strictly forbidden when the Song dynasty ended. Some military officials who refused to surrender formed the
Sambyeolcho Rebellion and resisted in the islands off the southern shore of the Korean Peninsula.
Mongol Invasions of Japan In 1266, Kublai Khan dispatched emissaries several times to Japan, demanding that Japan become a vassal and send tribute under the threat of conflict, some through Goryeo Emissaries but the
Kamakura shogunate despite the Japanese Imperial Court's request for compromise rejected them. The Mongols forced Goryeo to build warships to invade Japan, using their country as a stepping stone to conquer Japan through Kyushu, Tsushima, and their surrounding islands.
First Invasion The Yuan invasion force was composed of 15,000
Mongol,
Han Chinese, and
Jurchen soldiers, 6,000 to 8,000
Korean troops, and 7,000 Korean sailors. While the defending Japanese forces comprise 4,000 to 6,000 Japanese. They engaged the Japanese in conquering Tsushima, Iki Islands, and made landfall at Hakata Bay beginning the
Battle of Bun'ei. After landing in the bay, the Yuan force quickly overran the town of
Hakata (now a
ward of
Fukuoka), but were engaged by several samurai soon afterward. At first, the Yuan and Korean forces outnumbered the samurai, who were accustomed to smaller-scale clan rivalries; they could not match the organization and massed firepower of the invaders. Yuan forces fought with precision, loosing heavy volleys of arrows into the ranks of the Japanese. The Yuan also employed an early form of rocket artillery, and their infantry used
phalanx-like tactics, holding off the samurai with their shields and spears. Though unable to defeat the Yuan forces conclusively, the Japanese fought hard and inflicted heavy casualties. The Mongols burned
Hakozaki Shrine to the ground during the day's fighting. Despite their initial victories, the Yuan did not pursue the further samurai inland to the defenses at
Dazaifu.
Nihon Ōdai Ichiran explains that the Mongols lost due to their limited supply of arrows. More likely, this resulted from their unfamiliarity with the terrain, the expectation of Japanese reinforcements, and the heavy losses already suffered. The Yuan forces, which may have intended to carry out a survey in force rather than an immediate invasion, returned to their ships. That night, the Yuan lost roughly one-third of its force in a typhoon. They retreated to Korea, presumably at the prodding of their sailors and captains, rather than regrouping and continuing their attack.
Second Invasion More than 1,500 ships were requisitioned for the invasion: 600 from Southern China, 900 from Korea. Reportedly 40,000 troops were amassed in Korea and 100,000 in Southern China. Those numbers are likely an exaggeration, but the addition of Southern Chinese resources probably meant the second invasion force was still several times larger than the first invasion. Nothing is known about the size of the Japanese forces. By June 1281, 900 Yuan ships were gathered in Korea; the force was called the Eastern Route Army. They were crewed by 17,000 sailors, and transported 10,000 Korean soldiers and 15,000 Mongols and
Chinese. The Southern Route Army, meanwhile, was assembled just south of the
Yangtze River, in China. It is said to have consisted of 100,000 men on 3,500 ships. As before,
Iki and
Tsushima islands fell quickly to the much larger Yuan forces beginning the
Battle of Kōan. The Eastern Route Army arrived at Hakata Bay on June 23, and decided to proceed with the invasion without waiting for the larger Southern force which had still not left China. They were a short distance to the north and east of where their force had landed in 1274, and were in fact beyond the walls and defenses constructed by the Japanese. The samurai responded quickly, assaulting the invaders with waves of defenders, denying them the beachhead. At night small boats carried small bands of samurai into the Yuan fleet in the bay. Under cover of darkness they boarded enemy ships, killed as many as they could, and withdrew before dawn. This harassing tactic led the Yuan forces to retreat to Tsushima, where they would wait for the Southern Route Army. However, over the course of the next several weeks, 3,000 men were killed in close quarters combat in the hot weather. Yuan forces never gained a beachhead. The first of the Southern force ships arrived on July 16, and by August 12 the two fleets were ready to attack Japan. On August 15 a major tempest struck the
Tsushima Straits, lasting two full days and destroying most of the Yuan fleet. Contemporary Japanese accounts indicate that over 4,000 ships were destroyed in the storm; 80% of the Yuan soldiers either drowned or were killed by samurai on the beaches. The loss of ships was so great that "a person could walk across from one point of land to another on a mass of wreckage". and escaping Mongolians and Goryeo soldiers
Independence Gongmin regained Goryeo's Independence in the mid 14th century, and afterward Generals
Ch'oe Yŏng and
Yi Sŏng-gye rose to prominence with victories over invading
Red Turban armies from the north and
Wokou marauders from the south.
Repelling the Yuan King
Gongmin was forced to spend many years at the Yuan court, being sent there in 1341 as a virtual prisoner before becoming king. He married the Mongol
Princess Noguk as the queen consort. In the mid-14th century, the Yuan dynasty was beginning to crumble due to the Red Turban Rebellion. He used the conflict to reform the Korean government, abolish Mongolian military outposts, purge pro-Yuan sentiments, and regain lost northern territories such as
Liaoyang. The Goryeo army retook these provinces partly thanks to defection from
Yi Jachun, a minor Korean official in service of Mongols in
Ssangseong, and his son Yi Sŏng-gye. In addition, Generals Yi Sŏng-gye and Ji Yongsu led a campaign into
Liaoyang and conquered it in 1356. The final attempt by the Yuan to dominate Goryeo failed when General Ch'oe Yŏng defeated an invading Mongol
tumen in 1364. ====
Red Turban Rebellion==== The Red Turbans attacked Goryeo, most likely because of military necessity. In December 1359, part of the Red Turban army moved their base to the
Liaodong Peninsula. However, they were experiencing a shortage of war materials and lost their withdrawal route to the Chinese mainland. The Red Turban army led by
Mao Ju-jing invaded Goryeo and took the city of
Pyongyang. In January 1360, the Goryeo army led by
An U and
Yi Bang-sil retook Pyongyang and the northern region that the enemy had captured. Of the Red Turban army that had crossed the
Yalu River, only 300 troops returned to Liaoning after the war. In November 1360, the Red Turban troops invaded Goryeo's northwest border with 200,000 troops again, and they occupied
Gaegyeong, the capital of Goryeo, for a short period, King Gongmin escaped to
Andong. However, Generals
Ch'oe Yŏng, Yi Sŏng-gye (later
Taejo of Joseon),
Jeong Seun and
Yi Bang-sil repulsed the Red Turban army.
Sha Liu and
Guan Xiansheng, who were Red Turban generals, were killed in the battles. The Goryeo army continually chased their enemy and repelled them from the Korean Peninsula.
Wokou Raids The Mongol Invasions reduced the coastal defense capabilities of Goryeo, and the Wokou Pirates gradually intensified their looting on the coasts of Goryeo.
Chŏng Mong-ju was dispatched to Japan to deal with the problem, and during his visit Kyushu governor
Imagawa Sadayo suppressed the early wokou, later returning their captured property and people to Korea. According to Korean records, Wako pirates were particularly rampant roughly from 1350. After almost annual invasions of the southern provinces of
Jeolla and
Gyeongsang, they migrated northwards to the
Chungcheong and
Gyeonggi areas. The
History of Goryeo has a record of sea battles in 1380 whereby one hundred warships were sent to
Jinpo to rout Japanese pirates there, releasing 334 captives, Japanese sorties decreasing then after. The Wako pirates were effectively expelled through gunpowder technology, which the Wako lacked after Goryeo founded the Office of Gunpowder Weapons in 1377 (but abolished twelve years later). ==Organization==