Sukjong of Joseon

In the early years of Sukjong's reign, the Southern faction and Western faction clashed over the Royal Funeral Dispute, a seemingly minor issue regarding the mourning period for Queen Insun. The Southern faction claimed that the mourning period should last one year while the Western faction argued for a nine-month mourning period. A one-year mourning period meant that Hyojong of Joseon was considered the eldest son while 9-month period would suggest that Hyojong was considered not the eldest son, following the rules that governed the yangban class. In other words, the Western faction viewed the royal family as the first of the yangban class rather than a separate class for which different rules applied. The two factions were also in conflict over the issue of fighting the Qing Dynasty, which was considered barbaric country (as opposed to Ming Dynasty) that threatened Joseon's national security. The Southern faction, led by Heo Jeok and Yun Hyu, supported war against Qing while Western factions wanted to focus first on improving domestic conditions.

Sukjong at first sided with the Southern faction, but in 1680, Heo Jeok was accused of treason by Western faction, which led to the execution of Heo Jeok and Yun Hyu and purging of the Southern faction. This incident is called Gyeongsin hwanguk (경신환국). Once in power, the Western faction split into the Noron (Old Learning) faction, led by Song Si-yeol, and the Soron (New Learning) faction, led by Yun Jeung. After nine years in power, the Noron collapsed when Sukjong deposed Queen Min (posthumously called Queen Inhyeon), who was supported by the Western faction, and named Consort Hui of the Jang clan (also called Consort Jang or Jang Hui-bin) as the new queen. She is widely thought to be one of the most beautiful women of Joseon, her beauty mentioned in the Annals. The Western faction angered Sukjong when it opposed the naming of Consort Jang's son as crown prince. The Southern faction, who supported Consort Jang and her son, regained power and drove out Western faction, executing Song Si-yeol in revenge. This is called Gisa Hwanguk (기사환국).

Five years later in 1694, as the Southern faction planned another purge of the Western faction, accusing them of conspiracy to reinstate the deposed Queen, Sukjong began to regret deposing Queen Min and favored Consort Suk of the Choe clan, an ally of the Queen and the Noron faction. Angry with the Southern faction's attempt to purge Westerners, Sukjong abruptly turned around to purge Southerners and brought the Western faction back to power. The Southern faction would never recover from this blow, also called Gapsul Hwanguk (갑술환국). Sukjong demoted Queen Jang to her previous title (Jang Hui-bin) and reinstated Queen Min. Consort Jang was eventually executed by poison for cursing the Queen. The Soron faction supported Crown Prince Yi Yun, Consort Jang's son, while the Noron faction supported Consort Choe's son, Prince Yeoning (Yi Geum), later to become Yeongjo of Joseon. The late Queen Inhyeon and the newly installed Queen Kim (posthumously known as Queen Inwon) were both childless.

In 1718, Sukjong allowed the crown prince, soon to be Gyeongjong of Joseon, to rule as regent. Sukjong died in 1720 supposedly after telling Yi Yi-myoung to name Prince Yeoning as Gyeongjong's heir - in absence of a historiographer or recorder. This would lead to yet another purge in which four Noron leaders were executed in 1721, followed by another purge with the executions of eight Noron members in 1722.

Sukjong's accomplishments include tax reform (大同法), the creation of a new monetary system and currency (Korean mun), and the liberalization of civil service rules promoting the middle class and children of concubines into higher-ranking regional government positions.

In 1712, Sukjong's government worked with the Qing Dynasty in China to define national borders between the two countries at the Yalu and Tumen Rivers. The Japanese government recognized Ulleung Island as Joseon's territory in 1696 (the South Korean government insists that Liancourt Rocks was also recognized,[2] while the Japanese government disagrees).[3]

Sukjong's reign also saw agricultural development in remote provinces and increased cultural activity including publishing. He died after reigning for 46 years in 1720 at age 60. He was buried in Myeongneung (명릉) in Goyang, Gyeonggi Province, inside the Five Western Royal Graves (서오릉, 西五陵; Seooneung).