Jeong Yak-yong

Jeong Yak-yong, also called Jeong Yag-yong, was a Korean philosopher in the Joseon Dynasty. He was also a thinker in the "Practical Learning", (silhak).
Life.
Jeong was born, and died in Namyangju, Gyeonggi province.
Government service.
Jeong served the government most of his whole life. He watched over the building of Hwaseong fortress in Suwon in the 1790s. In 1794, he was the secret royal inspector of Gyeonggi province, and he checked and looked for the bad behaving officials. This later inspired his writings.
Names.
At different times in his life, Jeong had many kinds of "ho", or pen names. The most famous name was Dasan, which meant "tea mountain." Jeong used it while in his exile near a mountain of the same name, in Gangjin County, on the coast of South Jeolla province. Other pen names of his include Sammi (삼미/三眉), Yeoyudang (여유당/與猶堂), Saam (사암/俟菴), Jahadoin (자하도인/紫霞道人), Tagong (탁옹/籜翁), Taesu (태수/苔叟), Munamirin (문암일인/門巖逸人), and Cheolmasancho (철마산초/鐵馬山樵).
At birth, his father gave Jeong the name Gwinong, (귀농/歸農). Gwinong meant "returning to the land." As a Roman Catholic, Jeong had the baptized name John, or 요한 (Yohan), in Korean.
After his death, the King gave Jeong the special name Mundo (문도/文度). "Mun" meant writing or literature, and "do" meant law.