In this paper, I argue that Seong-yo 星要 (Essence of Stars), a manuscript kept in the National Library of Korea, was written by Nam Byeong-cheol (南秉哲, 1817~1863) and that it is likely to be the only book in pre-modern Korea dealing with Western horoscopic astrology. Nam reproduced the contents from Zhongxi　xingyao 中西星要 (Essence of Stars in China and West) by Ni Ronggui (倪榮桂, 1755~?), who was a fortune-teller in the late 18th century China. Ni Ronggui extracted his contents from Tianbu zhenyuan 天歩真原 (The Principles of the Pacing of the Heavens), which had been written cooperatively by Jesuit missionary Nikolaus Smolglecki (Mu Nige 穆尼閣, 1610~1656) and Xue Fengzuo (薛鳳祚, 1600~1680), a Chinese scholar. Western horoscopic astrology of Tianbu zhenyuan originated from the earlier books of Islamic and European one, which had started from Claudius Ptolemy's (ca. 2C.) Tetrabiblos. Therefore we can conclude that horoscopic astrology in Seongyo originated from the Greek astrology, which was approximately 1,700 years old at the time of Seongyo’s publication.