Wikipedia
Manjǒk (or spelled as Manjeok) ( Korean: 만적; 萬積) (?-1198) was a slave in Goryeo era Korea. It is said that he was a slave of Choe Chung-heon, a powerful military dictator at that time.
During the reign of Ŭijong (1146-1170), the government relaxed the restrictions toward slaves and eunuchs by allowing them to take low offices, which caused some governmental irregularities. In the reign of Myŏngjong (1170-1197) also saw the rise of the status of slaves. In 1197, Choe Chung-heon forced Myŏngjong to abdicate, put Sinjong on the throne, and became a military ruler with de facto control. During his government, Choe Chung-heon was less tolerant toward slaves, and several incidents involving slaves occurred in different places in Goryeo.
Manjǒk and some other slaves plotted a rebellion in 1198 against their masters in Kaesong, the capital of Goryeo. A speech of his that questioned inequality was recorded in the history book Goryeosa . Another slave revealed the plot to his own master, and the plot failed. Manjǒk and many other slaves were executed.