Jeongjo

King Jeongjo founded the Gyujanggak, a royal library and research institute in Seoul. It housed a vast collection of books and served as a center for scholarly research and policy development, promoting practical learning (sirhak).

King Jeongjo actively supported the Sirhak scholars, who advocated for practical reforms in agriculture, commerce, and technology. He appointed them to government positions and encouraged their research, fostering an intellectual renaissance in late Joseon.

King Jeongjo ordered the suppression of Catholicism in Joseon, executing several converts and banning the religion. This action was motivated by concerns over foreign influence and the perceived threat to Confucian social order.

King Jeongjo implemented the Suyang system, a military reform that reorganized the royal guard and local defense forces. He also introduced new weapons and training methods, strengthening Joseon's military capabilities.

King Jeongjo ordered the construction of Hwaseong Fortress in Suwon to honor his father Prince Sado and to establish a new administrative center. The fortress was built using advanced construction techniques and included a planned city. It is now a UNESCO World Heritage site.