李滉
After the death of his master, Jeong Gu and Heo Mok went to Jeong Gu's best pupil, Yeo-hun Chang Hyon-kwang's private educational institute. In later years, Heo Mok went to the jabong mountains(紫峯山), which he used as the place devoted to the reading and study of Confucianism. Jeong Gu had studied under Cho Shik and Yi Hwang. Yi Hwang's more academically and ideologically successful pupils joined the political faction Easterners and later the political faction Southerners. Cho Shik's pupil and academic successor--Jeong Gu--was in the political faction Easterners(동인;東人), and later the political faction Northerners. Despite being a pupil of Cho Shik, Jeong Gu used relations with his other teacher Yi Hwang to join the political faction Southerners.