King Gwanghaegun or Prince Gwanghae (Hanja: 光海君; Born: 3 June 1575 – Died: 7 August 1641; reigned 1608–1623), born Yi Hon (이혼/李琿), was the fifteenth king of the Joseon Dynasty. Since he was deposed in a coup, later official historians did not give him a temple name like Taejo or Sejong. He was married to Lady Ryu.
Gwanghaegun was the second son of King Seonjo, born to Lady Kim (Gongbin), a concubine. When Japan invaded Korea to attack the Ming Empire, he was installed as Crown Prince. When the king fled north to the border of Ming, he set up a branch court and fought defensive battles. During and after the Seven Year War (1592–1598), he acted as the de facto ruler of the Joseon Dynasty, commanding battles and taking care of the reconstruction of the nation after the devastating wars, in the place of old and weak King Seonjo.
Although it brought prestige to him, his position was still unstable. He had an elder but incompetent brother Prince Imhae (임해군/臨海君) and a younger but legitimate brother Grand Prince Yeongchang (영창대군/永昌大君), who was supported by the Lesser Northerners faction. Fortunately for Gwanghae, King Seonjo's abrupt death made it impossible for his most favorite son Grand Prince Yeongchang to succeed to the throne.
When King Seonjo died, he named Prince Gwanghae as his official successor to the throne, and ordered his advisers to make a royal document. However, Ryu Young-gyong of Lesser Northerners faction hid the document and plotted to install Prince Yeong-chang as king, only to be found out by the head of Great Northerners faction (북인/大北), Jeong Inong. Ryu was executed immediately and Grand Prince Yeongchang was arrested and died the next year.
After the incident, Gwanghae tried to bring officials from various political and regional background to his court, but his plan was interrupted by Greater Northerners including Lee Icheom and Jeong Inong. Then Greater Northerners began to take members of other political factions out of the government, especially Lesser Northerners. At last in 1613 Greater Northerners put their hand on Grand Prince Yeongchang; his grandfather Kim Jenam was found guilty of treason and executed, while Grand Prince Yeongchang was sent into exile, where he was executed. At the same time Greater Northerners suppressed the Lesser Northerners; In 1618, Grand Prince Yeongchang's mother, Queen Inmok of Yeon-an Kim Clan, was stripped off her title and imprisoned. However, Gwanghae had no power to stop this even though he was the official head of the government.
Despite his bad reputation in later times, he was a talented and realistic politician. He endeavored to restore the country and sponsored restoration of documents. As a part of reconstruction, he revised land ordinance and redistributed land to the people; he also ordered the rebuilding of Changdeok Palace along with several other palaces. He was also responsible for the reintroduction of the hopae identification system after a long period of disuse.
In foreign affairs he sought a balance between the Ming Empire and the Manchus. Since he realized Joseon was unable to compete with Manchu military power, he tried to keep friendly relationship with the Manchus while the kingdom was still under the suzerainty of Ming, which angered Ming and dogmatic Confucian Koreans. The critically worsened Manchu-Ming relationship forced him to send ten thousand soldiers to aid Ming in 1619. However, the Battle of Sarhū ended in Manchu's overwhelming victory. The Korean General Kang Hong-rip lost two-thirds of his troops and surrendered to Nurhaci. Gwanghaegun negotiated independently for peace with the Manchus and managed to avoid another war. He also restored diplomatic relationship with Japan in 1609 when he reopened trade with Japan through Treaty of Giyu, and sent his ambassadors to Japan in 1617.
During his reign, Gwanghaegun encouraged publishing in order to accelerate reconstruction and to restore the kingdom's former prosperity. Many books came out during his reign, including the famous medical book Donguibogam - who written by Heo Jun, and several historical records were rewritten in this period. In 1616, tobacco was first introduced to Korea and soon popularized by many aristocratic noblemen.
In 1623 Gwanghaegun was deposed in a coup by the Westerners faction. He was confined first on Ganghwa Island and then on Jeju Island, where he died in 1641. He does not have a royal mausoleum like the other Joseon rulers. His and Lady Ryu's remains were buried at a comparatively humble site in Namyangju in Gyeonggi Province. The Westerners faction installed Grand Prince NeungYang Yi Jong as the sixteenth king Injo who promulgated pro-Ming and anti-Manchu policies, which resulted in two subsequent Manchu invasions.
Although Gwanghaegun is one of only two deposed kings who were not restored and given the temple name (the other one being King Yeonsan the Terrible, the tyrant who greatly contributed to the decline of the nation), many people consider him a victim of feuds between political factions. However he did a better job of caring for his country than his predecessor, or his successor King Injo. They both contributed to invasions—the Japanese invasions of Korea (1592–1598), the Seven Year War; and the Jeongmyo and Byeongja Manchu Invasions. In modern South Korea, Gwanghaegun is considered a great and wise king, not a despot.
King Gwanghaegun was buried at Songneung-ri san 65-beonji, JinGeon-eup, Namyangju City, Gyeonggi Province. Although he was deposed and not given the Temple Name (e.g: King Sejong the Great or King Taejo Yi Seong-gye), he was given long and tongue-twisted posthumous name. He was posthumously known as King Checheon Heung-woon Jundeok Honggong Shinseong Yeong-sook Heummun Inmu Seoryun Ipgi Myeongseong Gwangnyeol Yungbong Hyeonbo Mujeong Junghui Yecheol Jang-ui Jangheon Sunjeong Geon-ui Sujeong Changdo Sung-eop the Great (체천흥운준덕홍공신성영숙흠문인무서륜입기명성광렬융봉현보무정중희예철장의장헌순정건의수정창도숭업대왕/體天興運俊德弘功神聖英肅欽文仁武敍倫立紀明誠光烈隆奉顯保懋定重熙睿哲莊毅章憲順靖建義守正彰道崇業大王).