Yeonsangun of Joseon

Yeonsan-gun or Prince Yeonsan (; ; born 23 November 1476 – 20 November 1506, r. 1494–1506) born Yi Yung, was the 10th king of Korea's Joseon Dynasty. He was the eldest son of King Seongjong by his second wife, Deposed Queen Yun. He is often considered the worst tyrant of the Joseon Dynasty, and perhaps all of Korean history, notorious for launching two bloody purges of the seonbi scholar elite. He also seized a thousand women from the provinces to serve as palace entertainers, and appropriated the Seonggyungwan study hall as a personal pleasure ground. As a much-despised overthrown monarch, Yeonsan-gun did not receive a temple name.
Biography.
Execution of his mother.
Queen Yun, later known as the Deposed Queen Lady Yun, served Prince Yeonsan's father, Seongjong, as a concubine until the death of Queen Gonghye, Seongjong's first wife. With no royal heir, the King was urged by counselors to take a second wife to secure the royal succession. Lady Yun was chosen for her beauty, and was formally married in 1476. Several months later, she gave birth to her first son, "Yi Yung", later to become Prince Yeonsan. The new Queen proved to be temperamental and highly jealous of Seongjong's concubines living inside the palace, even poisoning one in 1477. In 1479, she physically struck the King one night, leaving scratch marks. Despite efforts to conceal the injury, Seongjong's mother, Grand Queen Insu, discovered the truth and ordered Lady Yoon into exile. After several popular attempts to restore the deposed Queen Yun to her position at court, government officials petitioned that she be executed. She was later executed by poison.
Two purges.
The Crown Prince grew up and succeeded Seongjong in 1494. During his early reign, he was a wise and able administrator who strengthened the national defense and aided the poor. However, he also showed signs of a violent side when he killed Jo Sa-seo, one of his tutors, soon after becoming the king. He eventually learned of what had happened to his biological mother and attempted to posthumously restore her titles and position. When government officials belonging to the Sarim political party opposed his efforts on account of serving Seongjong's will, he was displeased and looked for ways to eliminate them. In 1498 Kim Il Son, a disciple of Kim Jong-jik, included a paragraph in the royal record that was critical of King Sejo's usurpation of throne in 1455. Kim Il-son and other followers of Kim Jong-jik were accused of treason by a rival faction, giving Yeonsangun cause enough to order the execution of many Sarim officials and the mutilation of Kim Jong-jik's remains. This came to be known as the First Literati Purge (무오사화 戊午士禍).
In 1504, Im Sa-hong revealed to Yeonsangun details of his mother's death and showed him a blood-stained piece of clothing, the blood allegedly vomited by her after taking poison. Soon afterward, on March 20, 1504, Yeonsangun beat to death two of his father's concubines, "Gwi-in" Jeong and Eom, for their part in his mother's death. His grandmother, Grand Queen Insu, formally the Queen Sohye, died when she was pushed by Yeonsangun after an altercation. He executed many government officials who had supported the execution of his mother, now posthumously known as Queen Jeheon, and ordered the grave of Han Myeong-hoi to be opened and the head cut off the corpse. He even punished officials known simply to be present at the royal court at that time, for the crime of not preventing the actions of those who abused his mother. Meanwhile, Im Sa-hong was promoted, and he and his allies received many important offices and other awards. This came to be known as the Second Literati Purge (갑자사화 甲子士禍).
Suppression of speech and learning.
Yeonsangun closed Seonggyeongwan, the royal university, as well as the Wongak-sa Temple, and converted them to be his personal pleasure grounds, for which young girls and horses were gathered from the whole of the Korean Peninsula. He intended to open personal brothels in their place. He demolished a large residential area in the capital and evicted 20,000 residents to build hunting grounds. He also forced people into involuntary labor to work on these projects. Many commoners mocked and insulted the king with posters written in hangul. This provoked the anger of Yeonsangun, and he banned the use of hangul and hanja.
When ministers protested against his actions, he abolished the Office of Censors (whose function was to criticize inappropriate actions or policies of the King) and Hongmoongwan (a library and research center that advised the King with Confucian teachings). He ordered his ministers to wear a sign that read: "A mouth is a door that brings in disaster; a tongue is a sword that cuts off a head. A body will be in peace as long as its mouth is closed and its tongue is deep within." (口是禍之門 舌是斬身刀 閉口深藏舌 安身處處牢).) When the chief eunuch Kim Cheo-sun, who had served three kings, entreated Yeonsangun to change his ways, Yeonsangun killed him by shooting arrows and personally cutting off his limbs, in addition Yeonsangun punished his relatives down to the 7th degree. When Yeonsangun asked the royal secretaries whether such punishment was appropriate, they did not dare to say otherwise. He also exiled a minister of rites for spilling a drink that he had poured.
In stark contrast to the liberal era of his father, many people became afraid of his despotic rule and their voices were silenced.
Dethronement.
In 1506, the 12th year of King Yeonsan, a group of officials – notably Park Won-jong, Seong Hui-ahn, Yoo Soon-jeong and Hong Gyeong-ju plotted against the despotic ruler. They launched their coup on 2 September 1506, deposing the king and replacing him with his half-brother, Grand Prince Jinseong. The king was demoted to prince, and sent into exile on Ganghwado, where he died the same year after only a few weeks. Consort Jang Nok-su, who was regarded as a 'femme fatale', had encouraged Yeonsangun's misrule, was beheaded. In addition, despite that the new king Jungjong was reluctant, Yeonsangun's four young sons also died because of forced suicide only a few weeks later.