Seonjo of Joseon (26 November 1552 – 16 March 1608) was the fourteenth king of the Joseon dynasty of Korea from 1567 to 1608. He was known for encouraging Confucianism and renovating state affairs at the beginning of his reign. However, he later gained infamy from political discord and incompetent leadership during the Japanese invasions of Korea.
King Seonjo was born Yi Yeon in 1552 in Hanseong (today, Seoul), capital of Korea, as the third son of Prince Deokheung (덕흥군), himself son of King Jungjong and Royal Noble Consort Chang of the Ansan Ahn clan (창빈 안씨). On his mother's side, Yi Yeon was also a great-great-great-grandson of Princess Jeongui, the daughter of Queen Soheon and King Sejong. Princess Jeongui's granddaughter, Lady Ahn of the Juksan Ahn clan, married Jeong Sang-jo (정상조, 鄭尙祖), his great-grandfather and son of Jeong In-ji through his second wife, Lady Yi of the Gyeongju Yi clan. As well as Jeong Sang-jo being the younger half-brother of Jo Gwang-jo.
He was given the title of Prince Haseong, and was eventually adopted by Queen Insun. When King Myeongjong died young without an heir, Prince Haseong was the next in the line of succession. Then, by decision of the royal court, he was crowned king in 1567 at the age of 16. His father had the status of Grand Internal Prince (대원군, Daewongun, 'Great Prince of the Court).
King Seonjo focused on the improvement of the lives of the common people, as well as rebuilding the nation after the political corruption during the chaotic reign of Yeonsangun and King Jungjong. He encouraged Sarim scholars, who had been persecuted by entrenched aristocrats in four different purges between 1498 and 1545 during reign of Yeonsangun and Jungjong. Seonjo continued the political reforms of King Myeongjong, and put many famous Confucian scholars, including Yi Hwang, Yi I, Jeong Cheol, and Yu Seong-ryong, in office.
Seonjo also reformed the civil service examination system, particularly the civil official qualification exam. The previous exam was mainly concerned with literature, not with politics or history.