Jeongjo of Joseon

Yi San was born 28 October 1752, second son to Crown Prince Sado, whose execution he witnessed as a boy, and Lady Hyegyŏng. He took the throne in 1776 after his grandfather King Yeongjo died, inheriting both a kingdom riven by factions and a reform agenda he sharpened into his own. He kept Yeongjo's Tangpyeong balancing policy but shifted the method: recruit the best minds, faction be damned. He built the Kyujanggak Royal Library, raised Hwaseong Fortress, published legal codes and literary collections, and formed the Jangyongyeong Guard. But placing Hong Guk-yeong too close let a retainer bend state business, and his final insurance move - marrying his young heir to Kim Jo-sun's daughter from the Andong Kim clan - backfired: it handed one family the lever and opened the door to decades of Sedo politics, the in-law rule that would hollow the dynasty. He died 18 August 1800, honored later as Emperor Seon, remembered now as one of Korea's greatest kings and the man who presided over a renaissance he couldn't make last.