King Sunjo

Sunjo was the 23rd king of Joseon, ascending the throne as a child in 1800 and ruling until 1834. During his reign, the Andong Kim clan—relatives of the royal family by marriage—seized power, marking the full onset of in-law politics (sedo), while major upheavals followed, including the Sinyu Persecution of Catholics and Hong Gyeong-rae's Rebellion, which arose from resentment over discrimination against the northwestern region. His era is regarded as a turning point at which the political and social turmoil of late Joseon deepened.